They are now 10 feet from the entrance.

Instead of checking the illusion, they instead act as if it was real, crawling past it (amorphous feature).

Quote from InkedBee >>

Maerwyn will cast Minor Illusion to create the image of an trap door inside the passage so that it's partially blocking the path (5 feet cube, length of the diagonal is around 8 feet) within the range of 30 feet. Investigation check against Spell Save DC 16 should reveal it as an illusion. Both of the creatures must make Wisdom Saving Throws to ignore the effect of the previously cast spell Slow.

If one of the creatures attempt to pass through it, she's going to use her bonus action to Grapple it with her Grappling Hook.

Grapple Check: 19

Quote from Cyb3rM1nd >>

OOC:

Slow is Wisdom.

Grappling Hooks can't grapple people. They're used for climbing. The only way to make it grapple is to have it swing around the target and latch back onto itself - which, given these are Large creatures in a narrow shaft, would be physically impossible. 

(@Orange20, @Cyb3rm1nd, I edited the post to fix the issue with the Wisdom Saving Throws. I've only used the Strength Modifier (+2) for the Grapple Check. Although Grappling Hook is an adventuring gear, I'm inclined to use it as an improvised weapon (Improvise). So, the creature must roll for Strength or Dexterity to escape the grapple.)

Quote from InkedBee >>

Quote from InkedBee >>

Maerwyn will cast Minor Illusion to create the image of an trap door inside the passage so that it's partially blocking the path (5 feet cube, length of the diagonal is around 8 feet) within the range of 30 feet. Investigation check against Spell Save DC 16 should reveal it as an illusion. Both of the creatures must make Wisdom Saving Throws to ignore the effect of the previously cast spell Slow.

If one of the creatures attempt to pass through it, she's going to use her bonus action to Grapple it with her Grappling Hook.

Grapple Check: 19

 

Quote from Cyb3rM1nd >>

OOC:

Slow is Wisdom.

Grappling Hooks can't grapple people. They're used for climbing. The only way to make it grapple is to have it swing around the target and latch back onto itself - which, given these are Large creatures in a narrow shaft, would be physically impossible. 

 

(@Orange20, @Cyb3rm1nd, I edited the post to fix the issue with the Wisdom Saving Throws. I've only used the Strength Modifier (+2) for the Grapple Check. Although Grappling Hook is an adventuring gear, I'm inclined to use it as an improvised weapon (Improvise). So, the creature must roll for Strength or Dexterity to escape the grapple.)

 *I'm going to rule that it's not something you can improvise to do it, since as Cyb3rm1nd said, it would be physically impossible.*

Maerwyn will use the feature of the Cloak of Arachnida to hang upside down from the ceiling and observe the movement of the Black Puddings.

(@Orange20, What's the current state of the Black Puddings? Did they leave the passageway?)

Quote from InkedBee >>

(@Orange20, What's the current state of the Black Puddings? Did they leave the passageway?)

 *Only 10 feet from entrance.*

Again reminding everyone that Grom gave you all flight and you can hover at any height

"Gentlemen, let's maintain social distance!"

Maerwyn will cast Thunderclap to trigger any kind of reaction that she expects from both of the creatures in order to lure them out of the passageway. The spell effect requires creatures (friendly/hostile) within the range of 5 feet to make Constitution Saving Throws against DC 16, on a failed save the creatures take 17 Thunder Damage.

If the creatures successfully get out of the pit and passage, Maerwyn will attempt to move the Grappling Hook attached with the rope in a swinging pattern in order to Grapple one of the creatures by using her bonus action.

Grapple Check: 13

Second Roll with Advantage (If applicable): 22

OOC:

So, to be clear Maerwyn went to the ceiling of the room (bearing in mind, it can only be the room since the shaft doesn't have one), and is now at least 30 ft away from the nearest pudding/ooze. She casts Thunderclap with a 5 ft range despite nothing being in that range, then tries to use a grappling hook to grapple except is too far away and the space in the shaft still doesn't allow this to be possible, which DM confirmed and nothing having changed, and you're using it as a bonus action even though it is an action and you don't have anything that lets you use it as a bonus.

I am considerably confused here.

Dusk will back away from the hole by about 20 ft and into the air by another 10 ft. He will have the Fire Spirit go to the hole Readying it's multiattack for when the first enemy gets within 5 ft. Wispy will come up to Dusk's side for protection.

Dusk will also ready a Mind Sliver cantrip for the moment an enemy appears through the hole in the floor.

(@Cyb3rm1nd, Mystic Frenzy feature would allow Maerwyn to attack as a bonus action after casting a cantrip. Checked. The sound of the spell can be heard up to 100 feet, so Maerwyn meant no damage to the creatures. Checked. Hempen rope has 50 feet length when Maerwyn can use her movement to fly 35 feet. Checked. So, the creature rolls for Strength or Dexterity to escape the grapple if it's outside the passageway. Please, remember to check out the character sheets before complaining, it's disrupting and the game loses the fun part.)

(@Orange20, Would you let Maerwyn improvise the action if the creature climbs up covering 10 feet distance? It will be physically possible, but it depends on you.)

OOC 

I was just trying to make sense of things. Like why are you describing thunderclap saving throws when you know there's nothing in range? Why is she luring them when they're already coming for us and having been lured by thunderclap twice (once my maerwyn, again by Magron - literally seconds before). The post was just very confusing. Like why is she intent on grappling them? I mean even if she manages to get the rope around them - it doesn't stop them moving, it's not like you're tying legs - they don't have any. It won't stop them advancing in any way. I mean sure, it might stop them moving away, but they're literally coming after us already, so what is the point here? They're big amorphous blobs, how is a simple circle of rope going to hold them when they can move through spaces the size a coin? Like seriously? 

Dusk would have spammed Mind Sliver, but I just didn't want to waste the effect on the saves against your entirely ineffectual grappling rope thing, his other cantrip is acid splash and he's already seen they're immune to that. 

They slow-moving creatures and we can fly. Just go in the air, range attack until dead from safety and move on. This is an easy encounter - why be fancy with weird rope things when if ya just attacked they'd be dead by now?

Quote from InkedBee >>

(@Orange20, Would you let Maerwyn improvise the action if the creature climbs up covering 10 feet distance? It will be physically possible, but it depends on you.)

 *I know that there's many facts, but isn't improvise an action? Doing that would take two actions and a bonus action, which she probably doesn't have.*

(@Cyb3rM1nd, let's see what happens when the creatures get out, I mean we can't take decisions without knowing their current conditions. So, wait for Orange to resolve the issue. And, the bold red letters hurt my eyes, nevermind.)

Quote from Orange20 >>

Quote from InkedBee >>

(@Orange20, Would you let Maerwyn improvise the action if the creature climbs up covering 10 feet distance? It will be physically possible, but it depends on you.)

 *I know that there's many facts, but isn't improvise an action? Doing that would take two actions and a bonus action, which she probably doesn't have.*

 (Maerwyn has extra attack feature, besides the grappling check is the improvised action. Instead of taking the attack action, I made her to replace it with the grappling check.)

Quote from InkedBee >>

Quote from Orange20 >>

Quote from InkedBee >>

(@Orange20, Would you let Maerwyn improvise the action if the creature climbs up covering 10 feet distance? It will be physically possible, but it depends on you.)

 *I know that there's many facts, but isn't improvise an action? Doing that would take two actions and a bonus action, which she probably doesn't have.*

 (Maerwyn has extra attack feature, besides the grappling check is the improvised action. Instead of taking the attack action, I made her to replace it with the grappling check.)

 *She cast a cantrip with a casting time of one action, and then used the improvise action.* 

Quote from Orange20 >>

 *I know that there's many facts, but isn't improvise an action? Doing that would take two actions and a bonus action, which she probably doesn't have.*

 (Maerwyn has extra attack feature, besides the grappling check is the improvised action. Instead of taking the attack action, I made her to replace it with the grappling check.)

 *She cast a cantrip with a casting time of one action, and then used the improvise action.* 

 (@Orange20, nope. She cast the spell(1 action), Grappling Check(1 bonus action replacing the Attack action, see Grapple, the Grappling Hook attached to the rope is an improvised weapon which will cost no action since interaction with an object doesn't require an action.)

Quote from InkedBee >>

Quote from Orange20 >>

 *I know that there's many facts, but isn't improvise an action? Doing that would take two actions and a bonus action, which she probably doesn't have.*

 (Maerwyn has extra attack feature, besides the grappling check is the improvised action. Instead of taking the attack action, I made her to replace it with the grappling check.)

 *She cast a cantrip with a casting time of one action, and then used the improvise action.* 

 (@Orange20, nope. She cast the spell(1 action), Grappling Check(1 bonus action replacing the Attack action, see Grapple, the Grappling Hook attached to the rope is an improvised weapon which will cost no action since interaction with an object doesn't require an action.)

 *Okay, but it actually is (I think).*

OOC: Thing is a grapple check that replaces an attack is you reaching out and grabbing them or using a weapon with an intended grapple-like function such as a net. You are using a grapple hook - which isn't a weapon - as an improvised weapon with a function it was not intended to have. Realistically this falls under Use An Object action, not an attack action. Also note the Grapple rules do indicate they can only use the attacks granted by the Attack action, so you cannot replace a bonus action attack. This is why the DM is confused.

((Can we stick to initiative order? I went twice in a row and now I'm not sure if I'm supposed to go again or its still others' turn.))