If you wouldn't allow bb to trigger (or more likely allow a PC/monster to stop their movements to avoid triggering bb) then it would a paradox about when triggering the OA in the first place.
Target stepped away more than 5' allowing an OA against him & being hit with bb.
Target noticed bb so stopped moving (stayed within 5').
If target stayed within 5' of attacker it wouldnt have triggered the OA in the first place.... so he shouldn't have been attacked at all..
There is no more a paradox than there is under the rules we all agree to:
Target stepped away more than 5' allowing an OA against them.
Player attempts an OA, but fails to because the target is out of reach (they already moved 5').
So obviously, that's not the correct order, let's try:
Target is within 5', and starts to move.
Player wants to perform an OA, but can't, because the target is still within 5'.
Target moves to outside of 5'.
Player attempts and OA, but fails (see above)
It's clear the the OA happens not when the target exits the 5', but when they're about to.
If they're about to exit, they still haven't, and unless something prevents them from choosing how they move (e.g. a Fear spell, the Sentinel Feat), they can choose to exit or not the space they're in. There is nothing under the OA rules that forces the target to complete, or even continue, their movement. Strictly RAW, they can decide to stop and not take the extra Booming Blade damage. A DM can choose to house rule that they are unable to stop that first 5' "step", or that they should roll a Dexterity saving throw, or Acrobatics check, or straight Dexterity roll, or whatever, to be able to choose whether to move or not, but that'd be strictly a house rule.
Consider a similar case:
Caster Readies a Booming Blade, specifying they'll cast it as soon as Target moves within 5' of them. Target begins to move, enters to a space within 5' of Caster, and Caster finishes their Booming Blade, applies base damage, and sheathes Target in booming energy. Now, can Target choose to stop moving, to avoid triggering the extra BB damage? Does it matter whether they were intending to stop there anyway, or whether they were intending to move past Caster?
If they're about to exit, they still haven't, and unless something prevents them from choosing how they move (e.g. a Fear spell, the Sentinel Feat), they can choose to exit or not the space they're in. There is nothing under the OA rules that forces the target to complete, or even continue, their movement. Strictly RAW, they can decide to stop and not take the extra Booming Blade damage. A DM can choose to house rule that they are unable to stop that first 5' "step", or that they should roll a Dexterity saving throw, or Acrobatics check, or straight Dexterity roll, or whatever, to be able to choose whether to move or not, but that'd be strictly a house rule.
I disagree. Refer to my last post about sequence: Trigger > Reaction > Resolve Attack & Immediate Effects > Continue Movement > Resolve Ancillary Effects.
There is nothing explicitly written because it is a chronological necessity that they continue moving the minimum 5 feet to leave the threatened square. There is no paradox of whether an effect applies immediately, or if a creature can choose to stop moving before leaving threat range; it does, and they can't.
The creature chose to leave the threatened square. The creature is punished for taking the risk by getting attacked on their way out. The creature finishes leaving the threatened square. The creature is further punished for taking that risk by taking Booming Blade damage. This is a necessity in order to resolve all ancillary effects of their decision to move that one square. The creature can now choose what to do with the rest of its turn.
I don't feel like this horse needs to be beaten to death, but maybe it will help to think about things from this perspective:
You've got a player standing at the edge of a volcano. One step forward, and they'll have to stop going by Anakin. They know how dangerous moving around a volcano is, and decide to try jumping across to the other side. They did not roll well enough to clear the entire distance.
Would you let that player say, "On second thought, I think I'll just walk around" because the 'bad thing' happened? No, they made a decision, and they have to live (or die) by the consequences of it. 🤷♂️
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You don't know what fear is until you've witnessed a drunk bird divebombing you while carrying a screaming Kobold throwing fire anywhere and everywhere.
I think the relevant portion of the rules are as follows:
"You can make an opportunity attack when a hostile creature that you can see moves out of your reach. To make the opportunity attack, you use your reaction to make one melee attack against the provoking creature. The attack occurs right before the creature leaves your reach."
"The opportunity attack, described later in this section, is the most common type of reaction. When you take a reaction, you can't take another one until the start of your next turn. If the reaction interrupts another creature's turn, that creature can continue its turn right after the reaction."
So Opportunity Attacks, unlike most Reactions, happen right before the target moves out of range and then the target CAN choose to continue their turn or not in response. Most of the time they are going to choose to do so otherwise they've taken a hit for nothing, but if they realize they've been hit by Booming Blade then they can choose not to.
The order of operations would be thus: Enemy Chooses to Move out of reach > Opportunity Attack interrupts this and goes before appreciable movement happens > Enemy chooses to move out of range and take the thunder damage or not.
If they choose not to move, they stop while they're still within reach, perhaps having moved only 4ft or so.
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Canto alla vita alla sua bellezza ad ogni sua ferita ogni sua carezza!
I sing to life and to its tragic beauty To pain and to strife, but all that dances through me The rise and the fall, I've lived through it all!
So Booming Blade obviously triggers on the Opportunity Attack before the target leaves melee. If the only question is if the target would continue to move after it would require the enemy know what kind of effect it is via Arcana or Intelligence check with a significant DC, because if a magical force were surrounding me without knowledge of what it does the first instinct would be to run out of it.
Secondly, there would almost certainly be a Dexterity check to determine the target could stop the instant they were affected. Movement can certainly be split up, but considering it takes about half a turn (3 seconds) to travel 30 feet one can assume they aren't tip toeing around.
Much of the argument against it is trying to minimize a potent combination that requires investment in a feat and spell choice, one that would rarely come up in game. I'd be worried to have a feeling of singling one of my players out.
So Booming Blade obviously triggers on the Opportunity Attack before the target leaves melee. If the only question is if the target would continue to move after it would require the enemy know what kind of effect it is via Arcana or Intelligence check with a significant DC, because if a magical force were surrounding me without knowledge of what it does the first instinct would be to run out of it.
Secondly, there would almost certainly be a Dexterity check to determine the target could stop the instant they were affected. Movement can certainly be split up, but considering it takes about half a turn (3 seconds) to travel 30 feet one can assume they aren't tip toeing around.
Mmm ... I probably wouldn't require this.
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Canto alla vita alla sua bellezza ad ogni sua ferita ogni sua carezza!
I sing to life and to its tragic beauty To pain and to strife, but all that dances through me The rise and the fall, I've lived through it all!
You can make an opportunity Attack when a Hostile creature that you can see moves out of your reach.
Wouldn't that assume you only get the chance for OA when the target is already committed to leaving your melee range (5')? It seems as if the conclusion is already written in.
The Attack occurs right before the creature leaves your reach.
And that would make it sound like the attack is at the last possible moment of the targets movement (say, 4'11").
Sounds almost like a Counterspell and the movement is the spell. Once the commitment to the movement is made for at least 5' for Opportunity Attack, or else it couldn't trigger by RAW, the OA happens around somewhere between 4' to 4'11" range. The extra 1" to 1ft would be willful movement, thus setting off Booming Blade. Both effects would trigger this way or else the OA would've never triggered to begin with.
As far as Sentinel, because it's going to be brought up:
Whenever you hit a creature with an opportunity attack, its speed drops to 0 for the rest of the turn. This stops any movement they may have been taking.
The bolded portion of the Sentinel feat explains why it works the same way. It retroactively negates any movement the target would have been taking.
You can make an opportunity Attack when a Hostile creature that you can see moves out of your reach.
Wouldn't that assume you only get the chance for OA when the target is already committed to leaving your melee range (5')? It seems as if the conclusion is already written in.
The Attack occurs right before the creature leaves your reach.
And that would make it sound like the attack is at the last possible moment of the targets movement (say, 4'11").
Sounds almost like a Counterspell and the movement is the spell. Once the commitment to the movement is made for at least 5' for Opportunity Attack, or else it couldn't trigger by RAW, the OA happens around somewhere between 4' to 4'11" range. The extra 1" to 1ft would be willful movement, thus setting off Booming Blade. Both effects would trigger this way or else the OA would've never triggered to begin with.
You're forgetting that this:
"The opportunity attack, described later in this section, is the most common type of reaction. When you take a reaction, you can't take another one until the start of your next turn. If the reaction interrupts another creature's turn, that creature can continue its turn right after the reaction."
... calls out opportunity attacks specifically as interruptions to a turn. Meaning that there is a distinct moment where the target can choose to to continue it's former plan of moving or not.
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Canto alla vita alla sua bellezza ad ogni sua ferita ogni sua carezza!
I sing to life and to its tragic beauty To pain and to strife, but all that dances through me The rise and the fall, I've lived through it all!
You can make an opportunity Attack when a Hostile creature that you can see moves out of your reach.
Wouldn't that assume you only get the chance for OA when the target is already committed to leaving your melee range (5')? It seems as if the conclusion is already written in.
The Attack occurs right before the creature leaves your reach.
And that would make it sound like the attack is at the last possible moment of the targets movement (say, 4'11").
Sounds almost like a Counterspell and the movement is the spell. Once the commitment to the movement is made for at least 5' for Opportunity Attack, or else it couldn't trigger by RAW, the OA happens around somewhere between 4' to 4'11" range. The extra 1" to 1ft would be willful movement, thus setting off Booming Blade. Both effects would trigger this way or else the OA would've never triggered to begin with.
You're forgetting that this:
"The opportunity attack, described later in this section, is the most common type of reaction. When you take a reaction, you can't take another one until the start of your next turn. If the reaction interrupts another creature's turn, that creature can continue its turn right after the reaction."
... calls out opportunity attacks specifically as interruptions to a turn. Meaning that there is a distinct moment where the target can choose to to continue it's former plan of moving or not.
I agree with the spirit of what you're getting at, I do. It just doesn't make sense how its written since the target has to move out of range for the trigger in the first place. They're already out of range directly after the Opportunity Attack or else it would've never occurred.
In terms of in game, the order would go: target moves out of reach to trigger OA -> OA attack on target -> target decides what to do next
But in terms of chronological order it would be: target moves away -> OA attack on target -> target finishes out of reach (to provoke OA to begin with) -> BB secondary damage -> target decides what to do next
I agree with the spirit of what you're getting at, I do. It just doesn't make sense how its written since the target has to move out of range for the trigger in the first place. They're already out of range directly after the Opportunity Attack or else it would've never occurred.
I don't agree. I think the specifics of the Opportunity Attack happening before the target moves out of range amends the general rule to effectively mean that an Opportunity Attack is triggered when a target attempts to move out of reach. After all, where would the body end up if an Opportunity Attack killed the target? I say it would still be in reach because the attack happened before it moved out of reach.
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Canto alla vita alla sua bellezza ad ogni sua ferita ogni sua carezza!
I sing to life and to its tragic beauty To pain and to strife, but all that dances through me The rise and the fall, I've lived through it all!
Interesting! Let's look at the relevant parts of the components.
Opportunity Attacks
You can make an opportunity attack when a hostile creature that you can see moves out of your reach. To make the opportunity attack, you use your reaction to make one melee attack against the provoking creature. The attack occurs right before the creature leaves your reach.
War Caster
When a hostile creature's movement provokes an opportunity attack from you, you can use your reaction to cast a spell at the creature, rather than making an opportunity attack. The spell must have a casting time of 1 action and must target only that creature.
Booming Blade
As part of the action used to cast this spell, you must make a melee attack with a weapon against one creature within the spell’s range, otherwise the spell fails. On a hit, the target suffers the attack’s normal effects, and it becomes sheathed in booming energy until the start of your next turn. If the target willingly moves before then, it immediately takes 1d8 thunder damage, and the spell ends.
So first off, it's very clear that a creature moving out of reach will trigger an opportunity attack and also that war caster allows that opportunity attack to be a spell, so therefore Booming Blade is allowed. There are various sage advice tweets from Jeremy Crawford confirming this with regards Booming Blade and Green-Flame Blade.
I guess there are several options, as the OP wrote.
RAW it seems that the point where the opportunity attack occurs, the target is still within 5' reach (see wording I bolded above).
We can assume that the creature is capable of instantly stopping, as the D&D rules have no sense of momentum and there are other abilities that can cause creatures to suddenly have zero movement and stop on the spot. So, it seems reasonable that the target can choose to instantly cease further movement if it wishes.
On immediately ceasing movement, the target's position is exactly where it was when the opportunity attack was triggered - right before it leaves your reach.
Thus it seems the creature is still within your reach.
So, it just comes down to whether the target chooses to stop or not. The options are:
The creature elects to stop immediately, which leaves it still in reach and doesn't trigger the secondary part of the booming blade spell.
The creature elects to continue moving and moves to where it planned, taking the opportunity attack and also being affected by the secondary part of the booming blade spell.
Whether the creature understands what has happened to it when the Booming Blade spell lands, and additionally whether it chooses to stop moving, is up to the DM.
This is just my take on the situation, based on the rules that are written down - I am not an official source of rules clarifications. :)
But if we say that the target can choose to stop before leaving reach, how would this play out? The target is still within 5' so it wouldnt trigger the initial OA in the first place.
How would it play out? with minis or even theater of the mind? The DM announces that the target is backing away but then doesnt? He moves the mini, realizes the attack then just moves it back to your adjacent square
Its supposed to be simultaneous, *as* the target backs away you take a swipe at him it only works by turn because it's a turn based game but it *is* still a simultaneous action
But if we say that the target can choose to stop before leaving reach, how would this play out? The target is still within 5' so it wouldnt trigger the initial OA in the first place.
How would it play out? with minis or even theater of the mind? The DM announces that the target is backing away but then doesnt? He moves the mini, realizes the attack then just moves it back to your adjacent square
Its supposed to be simultaneous, *as* the target backs away you take a swipe at him it only works by turn because it's a turn based game but it *is* still a simultaneous action
The OA was already triggered, the condition was met. The fact that the target decided not to move doesn't not invalidate that.
If you want a narrative, the target turned to run away, starting running, got hit with the OA, and froze in place, recognizing the booming energy, deciding it was more dangerous to take the extra damage than to stay in range of his opponent.
Interesting... I find Crawford's comment is not a definitive answer (nor official since it's not in the actual compendium, but w/e). He says "unless compelled" which can refer to various in-game effects, but I'd assert that having decided & taken action to leave a threatened space is also a compulsion. Momentum is a compulsion. You started moving and got up to speed. You're going to completely stop in one second? The top half of your body disagrees. Roll me an Athletics check to stop yourself from falling flat on your face.
Getting stabbed in the back is a pretty compelling reason to keep moving. Being in the middle of an unknown magic effect is a pretty compelling reason to keep moving. Unless Booming Blade is also one of your known spells, you don't know what that effect is. Roll me an Arcana or Intelligence check at disadvantage to see if you know what the effect is.
Bottom line: the heart of the issue--that I see us all still disagreeing on--boils down to what someone can reasonably do/be aware of/respond to during (and immediately following) the fraction of a turn that is a Reaction.
I don't think it's reasonable to completely stop unless the creature has been forced to stop by a condition or reduction of speed to zero.
I don't think it's reasonable to automatically know the details of Booming Blade just because you've been hit by it.
I don't think it's reasonable to change a specific portion of a creature's course of action when they've already committed to it. They knew the risks of leaving a threatened square prior to doing it. They made the conscious decision to do it anyway. What happens after leaving reach is up to the creature.
You don't know what fear is until you've witnessed a drunk bird divebombing you while carrying a screaming Kobold throwing fire anywhere and everywhere.
I think the argument that having previously decided to move is equivalent to a compulsion is somewhat facetious. Pretty sure "compulsion" is meant to be things like Compulsion or similar effects. Movement in D&D is not so simulationist as to imply some sort of conservation of momentum. You're right that not everyone is going to recognize the effects of Booming Blade and could continue moving in ignorance, but all other evidence goes to show that creatures can move and stop as they like during their movement.
Interesting... I find Crawford's comment is not a definitive answer (nor official since it's not in the actual compendium, but w/e).
I always caveat Sage Advice with the warning that SA is not RAW, though it is RAI. I see it as a valuable look into the minds and intentions of the designers. That being said, I also ignore Sage Advice when I don't like it :)
In this case, I don't really care for his advice. I'm going to play this the way I laid it out in my July 29th post because I see it as falling within the ambiguity of RAW for the situation. Target moves, BB is a reaction, melee attack hits. All of this happens simultaneously and now the target is now one square away and the aura is on them. Most creatures will continue moving without realizing the situation until it's too late, but particularly canny targets might catch on and stop moving. Also, this is an edge case and I wouldn't be surprised if this never happens in gameplay at a table I play or DM at.
That's my way. I'm not saying it's the one right way. I'm just saying I don't believe it is the wrong way.
Interesting... I find Crawford's comment is not a definitive answer (nor official since it's not in the actual compendium, but w/e).
I always caveat Sage Advice with the warning that SA is not RAW, though it is RAI. I see it as a valuable look into the minds and intentions of the designers. That being said, I also ignore Sage Advice when I don't like it :)
In this case, I don't really care for his advice. I'm going to play this the way I laid it out in my July 29th post because I see it as falling within the ambiguity of RAW for the situation. Target moves, BB is a reaction, melee attack hits. All of this happens simultaneously and now the target is now one square away and the aura is on them. Most creatures will continue moving without realizing the situation until it's too late, but particularly canny targets might catch on and stop moving. Also, this is an edge case and I wouldn't be surprised if this never happens in gameplay at a table I play or DM at.
That's my way. I'm not saying it's the one right way. I'm just saying I don't believe it is the wrong way.
I try to keep discussion on this forum to strict RAW, not RAI or "how I would run it", since it's a forum dedicated to rules and game mechanics. I do strongly believe RAW in this case means the target can choose to stop moving, to not exit the attacker's range, and therefore not take the extra BB damage after the Opportunity Attack. I would also run in that way in my games. On the other hand, I recognize that might not reflect reality very well (e.g. there's very little time to react to being hit), and while that doesn't bother me very much (after all, there are tons of other rules/situations that don't reflect reality very well, e.g. falling), I would have no problems whatsoever playing with a DM that used one of the other methods described in this thread, including "you can't stop moving until you reach the next square, so you end up 10' away, take the extra BB damage, and can then choose to keep moving or stop", "you can stop moving, but you might not know you want to, unless you roll an Arcana check to recognize the spell, or unless you've been targeted or have cast the spell before", "you can try to stop moving, but you need to roll a Dexterity check/save to see if you can stop in time", "you can't stop moving at all, you end up at your original intended destination, and suffer the extra BB damage" (I might have a problem with that one, since that would also imply that regardless of OAs or BB, you couldn't react to something you saw and stop or change your movement), or any combination thereof (e.g. "you'd need to roll Arcana to recognize it, then roll Dex to stop in time").
All this to say: some things in D&D 5e have "right" and "wrong" ways, some don't. ("Right" and "wrong" in quotes, because the only "wrong" way to play D&D is when nobody's having fun.) Issues where the rules are definitive (e.g. rolling an attack roll) aren't up for interpretation. Other issues are deliberately left up to the DM to decide. While there's nothing actually wrong with playing the "wrong" way (that is, DMs are entirely free to change, add, or remove any rules they want), this forum is mostly for discussing the "right" way (that is, without changing, adding, or removing any rules), or at least I try to treat it that way.
(Let me make it clear that I do not have anything whatsoever against DMs changing, adding, or removing rules from their games, or games I play in. I might have a problem with a specific change, but that's neither here nor there.)
All this talk of momentum. Are there really so many people who have never stopped suddenly before? And how much momentum can you even build up in just 1 step anyway?
I even found a research paper on the subject (https://www.ncbi.nlm.nih.gov/m/pubmed/9658047/). It seems to indicate that people can go from moving their full, normal gait to a full stop in 1 short half-step or less.
And since OA are one of few reactions that occur before the trigger, that means the target hasn't moved 5 feet yet before being struck. Now after having not yet moved a full space, they have an opportunity to notice the change with their body and stop (maybe taking 1 unintentional step that does not trigger BB or move them 5 feet) or choose to ignore the weird effect and continue moving.
This is why I think the optional stop without leaving threatened space after OA makes the most sense.
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There is no more a paradox than there is under the rules we all agree to:
So obviously, that's not the correct order, let's try:
It's clear the the OA happens not when the target exits the 5', but when they're about to.
If they're about to exit, they still haven't, and unless something prevents them from choosing how they move (e.g. a Fear spell, the Sentinel Feat), they can choose to exit or not the space they're in. There is nothing under the OA rules that forces the target to complete, or even continue, their movement. Strictly RAW, they can decide to stop and not take the extra Booming Blade damage. A DM can choose to house rule that they are unable to stop that first 5' "step", or that they should roll a Dexterity saving throw, or Acrobatics check, or straight Dexterity roll, or whatever, to be able to choose whether to move or not, but that'd be strictly a house rule.
Consider a similar case:
Caster Readies a Booming Blade, specifying they'll cast it as soon as Target moves within 5' of them. Target begins to move, enters to a space within 5' of Caster, and Caster finishes their Booming Blade, applies base damage, and sheathes Target in booming energy. Now, can Target choose to stop moving, to avoid triggering the extra BB damage? Does it matter whether they were intending to stop there anyway, or whether they were intending to move past Caster?
I disagree. Refer to my last post about sequence: Trigger > Reaction > Resolve Attack & Immediate Effects > Continue Movement > Resolve Ancillary Effects.
There is nothing explicitly written because it is a chronological necessity that they continue moving the minimum 5 feet to leave the threatened square. There is no paradox of whether an effect applies immediately, or if a creature can choose to stop moving before leaving threat range; it does, and they can't.
The creature chose to leave the threatened square. The creature is punished for taking the risk by getting attacked on their way out. The creature finishes leaving the threatened square. The creature is further punished for taking that risk by taking Booming Blade damage. This is a necessity in order to resolve all ancillary effects of their decision to move that one square. The creature can now choose what to do with the rest of its turn.
I don't feel like this horse needs to be beaten to death, but maybe it will help to think about things from this perspective:
You've got a player standing at the edge of a volcano. One step forward, and they'll have to stop going by Anakin. They know how dangerous moving around a volcano is, and decide to try jumping across to the other side. They did not roll well enough to clear the entire distance.
Would you let that player say, "On second thought, I think I'll just walk around" because the 'bad thing' happened? No, they made a decision, and they have to live (or die) by the consequences of it. 🤷♂️
You don't know what fear is until you've witnessed a drunk bird divebombing you while carrying a screaming Kobold throwing fire anywhere and everywhere.
I think the relevant portion of the rules are as follows:
"You can make an opportunity attack when a hostile creature that you can see moves out of your reach. To make the opportunity attack, you use your reaction to make one melee attack against the provoking creature. The attack occurs right before the creature leaves your reach."
"The opportunity attack, described later in this section, is the most common type of reaction. When you take a reaction, you can't take another one until the start of your next turn. If the reaction interrupts another creature's turn, that creature can continue its turn right after the reaction."
So Opportunity Attacks, unlike most Reactions, happen right before the target moves out of range and then the target CAN choose to continue their turn or not in response. Most of the time they are going to choose to do so otherwise they've taken a hit for nothing, but if they realize they've been hit by Booming Blade then they can choose not to.
The order of operations would be thus: Enemy Chooses to Move out of reach > Opportunity Attack interrupts this and goes before appreciable movement happens > Enemy chooses to move out of range and take the thunder damage or not.
If they choose not to move, they stop while they're still within reach, perhaps having moved only 4ft or so.
Canto alla vita
alla sua bellezza
ad ogni sua ferita
ogni sua carezza!
I sing to life and to its tragic beauty
To pain and to strife, but all that dances through me
The rise and the fall, I've lived through it all!
So Booming Blade obviously triggers on the Opportunity Attack before the target leaves melee. If the only question is if the target would continue to move after it would require the enemy know what kind of effect it is via Arcana or Intelligence check with a significant DC, because if a magical force were surrounding me without knowledge of what it does the first instinct would be to run out of it.
Secondly, there would almost certainly be a Dexterity check to determine the target could stop the instant they were affected. Movement can certainly be split up, but considering it takes about half a turn (3 seconds) to travel 30 feet one can assume they aren't tip toeing around.
Much of the argument against it is trying to minimize a potent combination that requires investment in a feat and spell choice, one that would rarely come up in game. I'd be worried to have a feeling of singling one of my players out.
I agree.
Mmm ... I probably wouldn't require this.
Canto alla vita
alla sua bellezza
ad ogni sua ferita
ogni sua carezza!
I sing to life and to its tragic beauty
To pain and to strife, but all that dances through me
The rise and the fall, I've lived through it all!
Well heck, it turns out this very question has been asked and answered by Jeremy Crawford, but it took someone linking it to me because I couldn't find it on my own. It turns out I was not completely wrong and also not completely right.
"Not all those who wander are lost"
After re-reading Opportunity Attack:
Wouldn't that assume you only get the chance for OA when the target is already committed to leaving your melee range (5')? It seems as if the conclusion is already written in.
And that would make it sound like the attack is at the last possible moment of the targets movement (say, 4'11").
Sounds almost like a Counterspell and the movement is the spell. Once the commitment to the movement is made for at least 5' for Opportunity Attack, or else it couldn't trigger by RAW, the OA happens around somewhere between 4' to 4'11" range. The extra 1" to 1ft would be willful movement, thus setting off Booming Blade. Both effects would trigger this way or else the OA would've never triggered to begin with.
As far as Sentinel, because it's going to be brought up:
The bolded portion of the Sentinel feat explains why it works the same way. It retroactively negates any movement the target would have been taking.
There needs to be cleaning up of rule terminology if this is the official position.
1. OA only triggers if an enemy leaves melee reach.
2. The hit happens right before the target leaves melee reach.
3. Completing the movement triggers Booming Blades second damage. There is no OA if they don't complete the movement as they never left melee range.
if they can stop before leaving the reach, there would be no chance of OA. It's a circular argument.
You're forgetting that this:
"The opportunity attack, described later in this section, is the most common type of reaction. When you take a reaction, you can't take another one until the start of your next turn. If the reaction interrupts another creature's turn, that creature can continue its turn right after the reaction."
... calls out opportunity attacks specifically as interruptions to a turn. Meaning that there is a distinct moment where the target can choose to to continue it's former plan of moving or not.
Canto alla vita
alla sua bellezza
ad ogni sua ferita
ogni sua carezza!
I sing to life and to its tragic beauty
To pain and to strife, but all that dances through me
The rise and the fall, I've lived through it all!
I agree with the spirit of what you're getting at, I do. It just doesn't make sense how its written since the target has to move out of range for the trigger in the first place. They're already out of range directly after the Opportunity Attack or else it would've never occurred.
In terms of in game, the order would go: target moves out of reach to trigger OA -> OA attack on target -> target decides what to do next
But in terms of chronological order it would be: target moves away -> OA attack on target -> target finishes out of reach (to provoke OA to begin with) -> BB secondary damage -> target decides what to do next
I don't agree. I think the specifics of the Opportunity Attack happening before the target moves out of range amends the general rule to effectively mean that an Opportunity Attack is triggered when a target attempts to move out of reach. After all, where would the body end up if an Opportunity Attack killed the target? I say it would still be in reach because the attack happened before it moved out of reach.
Canto alla vita
alla sua bellezza
ad ogni sua ferita
ogni sua carezza!
I sing to life and to its tragic beauty
To pain and to strife, but all that dances through me
The rise and the fall, I've lived through it all!
I (the OP) for one was very satisfied by Stormknight's answer and believe it is correct.
Yes, I like Stormknight's answer as well.
Canto alla vita
alla sua bellezza
ad ogni sua ferita
ogni sua carezza!
I sing to life and to its tragic beauty
To pain and to strife, but all that dances through me
The rise and the fall, I've lived through it all!
But if we say that the target can choose to stop before leaving reach, how would this play out? The target is still within 5' so it wouldnt trigger the initial OA in the first place.
How would it play out? with minis or even theater of the mind? The DM announces that the target is backing away but then doesnt? He moves the mini, realizes the attack then just moves it back to your adjacent square
Its supposed to be simultaneous, *as* the target backs away you take a swipe at him it only works by turn because it's a turn based game but it *is* still a simultaneous action
The OA was already triggered, the condition was met. The fact that the target decided not to move doesn't not invalidate that.
If you want a narrative, the target turned to run away, starting running, got hit with the OA, and froze in place, recognizing the booming energy, deciding it was more dangerous to take the extra damage than to stay in range of his opponent.
Interesting... I find Crawford's comment is not a definitive answer (nor official since it's not in the actual compendium, but w/e). He says "unless compelled" which can refer to various in-game effects, but I'd assert that having decided & taken action to leave a threatened space is also a compulsion. Momentum is a compulsion. You started moving and got up to speed. You're going to completely stop in one second? The top half of your body disagrees. Roll me an Athletics check to stop yourself from falling flat on your face.
Getting stabbed in the back is a pretty compelling reason to keep moving. Being in the middle of an unknown magic effect is a pretty compelling reason to keep moving. Unless Booming Blade is also one of your known spells, you don't know what that effect is. Roll me an Arcana or Intelligence check at disadvantage to see if you know what the effect is.
Bottom line: the heart of the issue--that I see us all still disagreeing on--boils down to what someone can reasonably do/be aware of/respond to during (and immediately following) the fraction of a turn that is a Reaction.
I don't think it's reasonable to completely stop unless the creature has been forced to stop by a condition or reduction of speed to zero.
I don't think it's reasonable to automatically know the details of Booming Blade just because you've been hit by it.
I don't think it's reasonable to change a specific portion of a creature's course of action when they've already committed to it. They knew the risks of leaving a threatened square prior to doing it. They made the conscious decision to do it anyway. What happens after leaving reach is up to the creature.
You don't know what fear is until you've witnessed a drunk bird divebombing you while carrying a screaming Kobold throwing fire anywhere and everywhere.
I think the argument that having previously decided to move is equivalent to a compulsion is somewhat facetious. Pretty sure "compulsion" is meant to be things like Compulsion or similar effects. Movement in D&D is not so simulationist as to imply some sort of conservation of momentum. You're right that not everyone is going to recognize the effects of Booming Blade and could continue moving in ignorance, but all other evidence goes to show that creatures can move and stop as they like during their movement.
Canto alla vita
alla sua bellezza
ad ogni sua ferita
ogni sua carezza!
I sing to life and to its tragic beauty
To pain and to strife, but all that dances through me
The rise and the fall, I've lived through it all!
I always caveat Sage Advice with the warning that SA is not RAW, though it is RAI. I see it as a valuable look into the minds and intentions of the designers. That being said, I also ignore Sage Advice when I don't like it :)
In this case, I don't really care for his advice. I'm going to play this the way I laid it out in my July 29th post because I see it as falling within the ambiguity of RAW for the situation. Target moves, BB is a reaction, melee attack hits. All of this happens simultaneously and now the target is now one square away and the aura is on them. Most creatures will continue moving without realizing the situation until it's too late, but particularly canny targets might catch on and stop moving. Also, this is an edge case and I wouldn't be surprised if this never happens in gameplay at a table I play or DM at.
That's my way. I'm not saying it's the one right way. I'm just saying I don't believe it is the wrong way.
"Not all those who wander are lost"
I try to keep discussion on this forum to strict RAW, not RAI or "how I would run it", since it's a forum dedicated to rules and game mechanics. I do strongly believe RAW in this case means the target can choose to stop moving, to not exit the attacker's range, and therefore not take the extra BB damage after the Opportunity Attack. I would also run in that way in my games. On the other hand, I recognize that might not reflect reality very well (e.g. there's very little time to react to being hit), and while that doesn't bother me very much (after all, there are tons of other rules/situations that don't reflect reality very well, e.g. falling), I would have no problems whatsoever playing with a DM that used one of the other methods described in this thread, including "you can't stop moving until you reach the next square, so you end up 10' away, take the extra BB damage, and can then choose to keep moving or stop", "you can stop moving, but you might not know you want to, unless you roll an Arcana check to recognize the spell, or unless you've been targeted or have cast the spell before", "you can try to stop moving, but you need to roll a Dexterity check/save to see if you can stop in time", "you can't stop moving at all, you end up at your original intended destination, and suffer the extra BB damage" (I might have a problem with that one, since that would also imply that regardless of OAs or BB, you couldn't react to something you saw and stop or change your movement), or any combination thereof (e.g. "you'd need to roll Arcana to recognize it, then roll Dex to stop in time").
All this to say: some things in D&D 5e have "right" and "wrong" ways, some don't. ("Right" and "wrong" in quotes, because the only "wrong" way to play D&D is when nobody's having fun.) Issues where the rules are definitive (e.g. rolling an attack roll) aren't up for interpretation. Other issues are deliberately left up to the DM to decide. While there's nothing actually wrong with playing the "wrong" way (that is, DMs are entirely free to change, add, or remove any rules they want), this forum is mostly for discussing the "right" way (that is, without changing, adding, or removing any rules), or at least I try to treat it that way.
(Let me make it clear that I do not have anything whatsoever against DMs changing, adding, or removing rules from their games, or games I play in. I might have a problem with a specific change, but that's neither here nor there.)
All this talk of momentum. Are there really so many people who have never stopped suddenly before? And how much momentum can you even build up in just 1 step anyway?
I even found a research paper on the subject (https://www.ncbi.nlm.nih.gov/m/pubmed/9658047/). It seems to indicate that people can go from moving their full, normal gait to a full stop in 1 short half-step or less.
And since OA are one of few reactions that occur before the trigger, that means the target hasn't moved 5 feet yet before being struck. Now after having not yet moved a full space, they have an opportunity to notice the change with their body and stop (maybe taking 1 unintentional step that does not trigger BB or move them 5 feet) or choose to ignore the weird effect and continue moving.
This is why I think the optional stop without leaving threatened space after OA makes the most sense.