Asger's Despicable Surprise

Store explosive necrotic energy within a dead creature and turn it into a deadly trap. The dead creature of which the spell is placed cannot be larger than large sized or smaller than small sized. Once the trap is set; you can choose a specific creature(s) and the trap will only be triggered when the chosen creature(s) enter within 10 feet of it. The trap can also be triggered with an action or reaction.  Upon activation of the trap, any creature within a 30 foot radius of the necrotic explosion must make a dexterity saving throw. Each creature will take 6d10 necrotic damage on a failed save, or half as much damage on a successful one. If nothing triggers the trap in 8 hours it automatically explodes and it cannot be dispelled without dispel magic. A chain reaction between multiple traps can occur but do not stack damage. For example, if two 5th level necrotic explosions overlap and hit the same creature the damage will still only be 6d10.

At Higher Levels. When you cast this spell using a 6th slot or higher, the damage increases by 1d10 for each slot above 5th.