Mordenkainen's Lost Notebook

Cryptwarden’s Grasp

5-level Necromancy

Make a melee spell attack against a living target. On a hit, you deal 6d6 necrotic damage and bestow in your target a magical effect essentially identical to mummy rot. The target must succeed on a DC 16 Constitution saving throw or be cursed. The cursed target can’t regain hit points, and its hit point maximum decreases by 3d6 for every 24 hours that elapse. If the curse reduces the target’s hit point maximum to 0, the target dies, and its body turns to dust. The curse lasts until removed by the remove curse spell or other magic.