Recently my group asked me if I could make a "corpse explosion" spell, which I'm all for because I feel 5e is really lacking in a good variety of necromancy spells, but they also wanted it to scale depending on the size of the corpse. After looking at several other homebrews, I couldn't find one that worked the way that I'd like for my group. What I have below is my current draft, and I know it is above normal damage scaling compared to other spells of this level, but that's due to the spell needing a proper corpse to function. Please give me your opinions on this because at the moment I feel this spell has potential, but unsure if the route I'm taking will work.
Name: Corpse Explosion
Level / School: 1st level necromancy
Casting time: 1 action
Range: 60 ft (radius varies)
Description:
You point an open hand towards a corpse, enveloping it with negative energy causing it to violently explode. Choose a corpse within range that you can see with a size of large or smaller to detonate. The size of the chosen corpse will determine both the radius sphere of the explosion and the damage dealt, as shown on the table below. Each creature in range of the explosion must make a Dexterity saving throw or take corresponding necrotic damage. On a successful save, creatures takes half as much damage.
Corpse Size
Damage
Radius
Tiny
2d4
5'
Small
2d6
5'
Medium
2d8
10'
Large
2d10
15'
Huge
2d12
20'
Gargantuan
4d8
30'
Some classifications of corpses are insufficient composition to detonate, such as constructs or oozes. Discuss the details with your DM to determine what conditions need to be met to cast this spell.
At Higher Levels. When you cast this spell using a spell slot of 2nd level or higher, the damage increases by one damage die, or two damage dice if the corpse belongs to a gargantuan size creature for each slot level above 1st. Using a spell slot of 3rd level or higher grants the ability to cast the spell on a huge size corpse. Using a spell slot of 5th level or higher grants the ability to cast the spell on a gargantuan size corpse.
The core idea of the spell seems sound, but be careful about the wording about the upcasting. And just as a potential balance suggestion, you might want to think if the condition of the corpse would be important (such as a fresh "living" corpse (i.e. died that same battle) vs. ancient corpse vs undead).
A rules-as-written interpretation could mean that the damage dice go up for gargantuan immediately after the first level, meaning that by the time you can target gargantuan sized corpses at level 5, the damage dice for gargantuan sizes at would be 12d8 with the damage die for level 9 being 20d8 (4d8 "at level 1", plus 2d8 per level above 1st).
Unless this is intentional, I would write out each category upgrade individually. Something along the lines of:
At Higher Levels. When you target a large or smaller creature while casting this spell using a spell slot of 2nd level or higher, the damage increases by one damage die for each slot level above the 1st. Using a spell slot of 3rd level or higher grants the ability to cast the spell on a huge size corpse with the damage die for a huge creature increasing by 1d12 for each slot level above the 3rd. Using a spell slot of 5th level or higher grants the ability to cast the spell on a gargantuan size corpse with the damage die for a gargantuan creature increasing by 2d8 for each slot level above the 5th.
I completely agree with that, but couldn't find a way to properly word it so that it covered each of those examples without being too convoluted. So instead, I added the snippet about "talk to your DM" for that specific reason and thought I'd leave it to be a discussion the player and DM. Though if you think it'd be better if I did more detailed write up for those examples I can, it would just be a bit.
As for the gargantuan damage scaling, that was purposeful. I originally based the damage die off the creature size health, but didn't like the jump from 1d12 to 1d20, so I went with 2d8 instead.
Leaving most of the corpse qualifications up to an agreement between DM and player might work, but keep in mind that if a spell is usable to the player it's also usable against a player - meaning corpses of PCs are fair targets (and the resurrection complications that might bring). I might suggest hard rules or at least a mention about how the spell interacts with "fresh" corpses, even if it's just to confirm or deny that PCs can be targeted once they fail all their death saves. Just to save any future DM the headache of players arguing if it would or not.
Recently my group asked me if I could make a "corpse explosion" spell, which I'm all for because I feel 5e is really lacking in a good variety of necromancy spells, but they also wanted it to scale depending on the size of the corpse. After looking at several other homebrews, I couldn't find one that worked the way that I'd like for my group. What I have below is my current draft, and I know it is above normal damage scaling compared to other spells of this level, but that's due to the spell needing a proper corpse to function. Please give me your opinions on this because at the moment I feel this spell has potential, but unsure if the route I'm taking will work.
You point an open hand towards a corpse, enveloping it with negative energy causing it to violently explode. Choose a corpse within range that you can see with a size of large or smaller to detonate. The size of the chosen corpse will determine both the radius sphere of the explosion and the damage dealt, as shown on the table below. Each creature in range of the explosion must make a Dexterity saving throw or take corresponding necrotic damage. On a successful save, creatures takes half as much damage.
Corpse Size
Damage
Radius
Tiny
2d4
5'
Small
2d6
5'
Medium
2d8
10'
Large
2d10
15'
Huge
2d12
20'
Gargantuan
4d8
30'
Some classifications of corpses are insufficient composition to detonate, such as constructs or oozes. Discuss the details with your DM to determine what conditions need to be met to cast this spell.
At Higher Levels. When you cast this spell using a spell slot of 2nd level or higher, the damage increases by one damage die, or two damage dice if the corpse belongs to a gargantuan size creature for each slot level above 1st. Using a spell slot of 3rd level or higher grants the ability to cast the spell on a huge size corpse. Using a spell slot of 5th level or higher grants the ability to cast the spell on a gargantuan size corpse.
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The core idea of the spell seems sound, but be careful about the wording about the upcasting. And just as a potential balance suggestion, you might want to think if the condition of the corpse would be important (such as a fresh "living" corpse (i.e. died that same battle) vs. ancient corpse vs undead).
A rules-as-written interpretation could mean that the damage dice go up for gargantuan immediately after the first level, meaning that by the time you can target gargantuan sized corpses at level 5, the damage dice for gargantuan sizes at would be 12d8 with the damage die for level 9 being 20d8 (4d8 "at level 1", plus 2d8 per level above 1st).
Unless this is intentional, I would write out each category upgrade individually. Something along the lines of:
At Higher Levels. When you target a large or smaller creature while casting this spell using a spell slot of 2nd level or higher, the damage increases by one damage die for each slot level above the 1st. Using a spell slot of 3rd level or higher grants the ability to cast the spell on a huge size corpse with the damage die for a huge creature increasing by 1d12 for each slot level above the 3rd. Using a spell slot of 5th level or higher grants the ability to cast the spell on a gargantuan size corpse with the damage die for a gargantuan creature increasing by 2d8 for each slot level above the 5th.
I completely agree with that, but couldn't find a way to properly word it so that it covered each of those examples without being too convoluted. So instead, I added the snippet about "talk to your DM" for that specific reason and thought I'd leave it to be a discussion the player and DM. Though if you think it'd be better if I did more detailed write up for those examples I can, it would just be a bit.
As for the gargantuan damage scaling, that was purposeful. I originally based the damage die off the creature size health, but didn't like the jump from 1d12 to 1d20, so I went with 2d8 instead.
My Homebrew | Background | Feats | Magic Items | Races | Spells | Subclass | Homebrewery
To see my more recent homebrew creations, please check out my content on Hombrewery.
Leaving most of the corpse qualifications up to an agreement between DM and player might work, but keep in mind that if a spell is usable to the player it's also usable against a player - meaning corpses of PCs are fair targets (and the resurrection complications that might bring). I might suggest hard rules or at least a mention about how the spell interacts with "fresh" corpses, even if it's just to confirm or deny that PCs can be targeted once they fail all their death saves. Just to save any future DM the headache of players arguing if it would or not.
Take a look at the Wildemont creature variant "Husk Zombie Burster."