I told my players (who are spellcasters) that they can create a spell, much like Melf's Acid Arrow, or Mordenkainen's Magnificient Mansion and the like. The character's name is Marcell and wants the spell to be called Marcell's Red Tide. Based on some event that happened in his backstory, the gist of the spell is it has the ability to corrode away a limb. I would like to use disintegrate as inspiration for the spell, but also make it different enough, that both disintegrate and red tide could be in a spellcaster's spellbook with each coming in handy in their own way.
Things I need:
Appropriate spell level
A save of some sort
Damage then erode limb, or just a check to erode the limb, or two fails to erode a limb, the first check dealing damage?
Alright, I like this, I encourage my players to come up with their own spells, weapons, and etc. I want them to feel free to make their own stuff as they acquire materials and resources.
Looking at a couple spells at the 4th level tier we're looking at 28 damage on average, something that can be met with 6d8 damage.
I'd then have to have a DC for the lost limb, however this is a severe injury so the DC would have to reflect this. You want the possibility of lost limb to be real, but you don't want to make it so that the caster can almost guarantee that it happens. The proficiency bonus at the time you can cast 4th level spells is +3. Assuming the caster is pushing for the best stats they'll have a +4 at minimum for their attribute bonus, this gives us a DC 15. Given that Con is generally not a strong save for most things in the game, we'll have to choose an Attribute that could allow a reasonable chance to avoid losing a limb. I'm going to push for a Dex save to avoid the beam striking an appendage.
From there it's a matter of whether you allow the caster to choose what appendage is lost. Not everyone will have a body die like I do, so that makes things tricky. If the caster can choose a limb then it's easy, otherwise you can simply roll a d4 to choose L/R arm or leg. However I prefer not to bog down the game with die rolls that aren't necessary, so I'm leaning toward calling the appendage. However I would not allow head shots to be a thing, instantly killing a creature on a failed save with a 4th level spell is way too strong.
Marcell's Red Tide 4th level necromancy
Casting Time: 1 action Range: 30 feet Components: V S Duration: Instantaneous Classes: Sorcerer, Wizard, Warlock
A narrow beam of dark red energy extents from the fingertips of the caster toward an appendage of a creature of your choice causing the targeted area to rot from the inside out. The target must make a Dexterity saving throw. The target takes 6d8 Necrotic damage on a failed saving throw, or half as much on a successful one. On a failed saving throw the target also loses the appendage targeted by the caster. The appendage is destroyed and may only be recovered by a Lesser/Greater Restoration or Regeneration spell. At Higher Levels: When you cast this spell using a spell slot of 5th level or higher, the damage increases by 1d8 for each slot level above 4th.
You can upcast a scorching ray to do 10d6 damage at level 4.
I still think it should be a CON save, maybe they could have to fail the save twice similar to the petrifying effects of the Gorgon or medusa.
It shouldn't be curable by lesser restoration, in fact it should probably only be curable with regenerate and if you are generous heal. Losing limbs does not have any specified downsides.
Losing limbs does not have any specified downsides.
Perhaps you could place the Lingering Injuries rules from the DMG in the spell:
Lose a Foot or Leg. Your speed on foot is halved, and you must use a cane or crutch to move unless you have a peg leg or other prosthesis. You fall prone after using the Dash action. You have disadvantage on Dexterity checks made to balance. Magic such as the regenerate spell can restore the lost appendage. Lose an Arm or a Hand. You can no longer hold anything with two hands, and you can hold only a single object at a time. Magic such as the regenerate spell can restore the lost appendage.
If you take Disintegrate as a base spell for this, why not make the spell so that if you deal X damage, the target loses the limb? This might be abstract like "If the damage equals or exceeds a third of the target's current hit points" or something like that? That way it does not interfere with Disintegrate itself (which requires you to go to 0), makes them both not mutually exclusive
I told my players (who are spellcasters) that they can create a spell, much like Melf's Acid Arrow, or Mordenkainen's Magnificient Mansion and the like. The character's name is Marcell and wants the spell to be called Marcell's Red Tide. Based on some event that happened in his backstory, the gist of the spell is it has the ability to corrode away a limb. I would like to use disintegrate as inspiration for the spell, but also make it different enough, that both disintegrate and red tide could be in a spellcaster's spellbook with each coming in handy in their own way.
Things I need:
Published Subclasses
Spell level can vary, but 4th level sounds about right.
Con save (Spell save DC)
Failed save: damage (somewhere around 11d6 necrotic) and lose limb (random?). Succeed save: half damage.
Alright, I like this, I encourage my players to come up with their own spells, weapons, and etc. I want them to feel free to make their own stuff as they acquire materials and resources.
Looking at a couple spells at the 4th level tier we're looking at 28 damage on average, something that can be met with 6d8 damage.
I'd then have to have a DC for the lost limb, however this is a severe injury so the DC would have to reflect this. You want the possibility of lost limb to be real, but you don't want to make it so that the caster can almost guarantee that it happens. The proficiency bonus at the time you can cast 4th level spells is +3. Assuming the caster is pushing for the best stats they'll have a +4 at minimum for their attribute bonus, this gives us a DC 15. Given that Con is generally not a strong save for most things in the game, we'll have to choose an Attribute that could allow a reasonable chance to avoid losing a limb. I'm going to push for a Dex save to avoid the beam striking an appendage.
From there it's a matter of whether you allow the caster to choose what appendage is lost. Not everyone will have a body die like I do, so that makes things tricky. If the caster can choose a limb then it's easy, otherwise you can simply roll a d4 to choose L/R arm or leg. However I prefer not to bog down the game with die rolls that aren't necessary, so I'm leaning toward calling the appendage. However I would not allow head shots to be a thing, instantly killing a creature on a failed save with a 4th level spell is way too strong.
Marcell's Red Tide
4th level necromancy
Casting Time: 1 action
Range: 30 feet
Components: V S
Duration: Instantaneous
Classes: Sorcerer, Wizard, Warlock
A narrow beam of dark red energy extents from the fingertips of the caster toward an appendage of a creature of your choice causing the targeted area to rot from the inside out. The target must make a Dexterity saving throw. The target takes 6d8 Necrotic damage on a failed saving throw, or half as much on a successful one. On a failed saving throw the target also loses the appendage targeted by the caster. The appendage is destroyed and may only be recovered by a Lesser/Greater Restoration or Regeneration spell.
At Higher Levels: When you cast this spell using a spell slot of 5th level or higher, the damage increases by 1d8 for each slot level above 4th.
Edit: Changed some language in the description.
You can upcast a scorching ray to do 10d6 damage at level 4.
I still think it should be a CON save, maybe they could have to fail the save twice similar to the petrifying effects of the Gorgon or medusa.
It shouldn't be curable by lesser restoration, in fact it should probably only be curable with regenerate and if you are generous heal. Losing limbs does not have any specified downsides.
Upcasting it should be 2 dice per level.
Perhaps you could place the Lingering Injuries rules from the DMG in the spell:
Lose a Foot or Leg. Your speed on foot is halved, and you must use a cane or crutch to move unless you have a peg leg or other prosthesis. You fall prone after using the Dash action. You have disadvantage on Dexterity checks made to balance. Magic such as the regenerate spell can restore the lost appendage.
Lose an Arm or a Hand. You can no longer hold anything with two hands, and you can hold only a single object at a time. Magic such as the regenerate spell can restore the lost appendage.
If you take Disintegrate as a base spell for this, why not make the spell so that if you deal X damage, the target loses the limb? This might be abstract like "If the damage equals or exceeds a third of the target's current hit points" or something like that? That way it does not interfere with Disintegrate itself (which requires you to go to 0), makes them both not mutually exclusive
Subclass: Dwarven Defender - Dragonborn Paragon
Feats: Artificer Apprentice
Monsters: Sheep - Spellbreaker Warforged Titan
Magic Items: Whipier - Ring of Secret Storage - Collar of the Guardian
Monster template: Skeletal Creature