Desecrate the Living

Flesh begins to slowly deteriorate underneath your dark influence, which grows in power from those weakened by it.  The caster creates a 20 ft. radius sphere centered on themselves, and creatures other the caster must make a Constitution saving throw, or take 4d4 necrotic damage and be weakened.  Any creature must also make a saving throw when it moves into the area of effect for the first time on a turn or ends its turn there.  This damage increases by 2d4 for every failed saving throw made during concentration.

Undead are immune to this spell.