Nilbog

Any creature that attempts to damage the nilbog must first succeed on a DC 12 Charisma saving throw or be Charmed until the end of the creature's next turn. A creature Charmed in this way must use its action praising the nilbog.
The nilbog can't regain hit points, including through magical healing, except through its Reversal of Fortune reaction.

Melee Weapon Attack +4 to hit, reach 5 ft., one target. 5 (1d6 + 2) Bludgeoning damage.

The nilbog targets one creature it can see within 60 feet of it. The target must succeed on a DC 12 Wisdom saving throw or take 5 (2d4) Psychic damage and have disadvantage on its next attack roll before the end of its next turn.

The nilbog takes the Disengage or Hide action.

In response to another creature dealing damage to the nilbog, the nilbog reduces the damage to 0 and regains 3 (1d6) hit points.