Edimmu

Rejuvenation. If destroyed, an edimmu rises again in 2d4 days. Permanently destroying one requires properly burying its mortal remains in consecrated or hallowed ground. Edimmus rarely venture more than a mile from the place of their death.

Incorporeal Movement. The edimmu can move through other creatures and objects as if they were difficult terrain. It takes 5 (1d10) force damage if it ends its turn inside an object.

Water Siphon. Melee Spell Attack: +7 to hit, reach 5 ft., one creature. Hit: 21 (6d6) necrotic damage. The target must succeed on a DC 14 Constitution saving throw or its hit point maximum is reduced by an amount equal to the damage taken and it is stunned for 1 minute and gains one level of exhaustion. A stunned creature repeats the saving throw at the end of each of its turns, ending the stun on itself on a success. The hit point reduction lasts until the creature finishes a long rest and drinks abundant water or until it is affected by greater restoration or comparable magic. The target dies if this effect reduces its hit point maximum to 0.