Mordenkainen's Lost Notebook

Blackmantle

6-level Necromancy

Choose a 15-foot radius area within range. Any living creature within the area must make a Constitution saving throw. On a failed save, the creature is outlined with a dark aura and it can’t benefit from healing or regeneration for the duration. In addition, the creature can’t benefit from invisibility whilst affected by this spell. An affected creature can make another saving throw at the end of each of its turns, ending the spell’s effect on it with a success
At higher levels: When you cast this spell using a spell slot of 7th level or higher, the radius of the effect increases by five feet for every slot level above 6th.