Corpse bomb

The caster targets an undead or recently slain corpse of a humanoid if undead is targeted they must make a constitution saving throw on a success nothing happens on a fail and on a corpse the body moves 30ft in a direction of your choice then explodes dealing 5d8 necrotic damage if a corpse or the undead is reduced to 0 hit points  also 2d6 bludgeoning damage constitution save for half damage.

For every level above 3rd this is cast add 1d8 necrotic damage