Hezrou

If the monster dies outside the Abyss, its body dissolves into ichor, and it gains a new body instantly, reviving with all its Hit Points somewhere in the Abyss.

The monster has Advantage on saving throws against spells and other magical effects.

Constitution Saving Throw: DC 16, any creature (other than the monster) that starts its turn in a 10-foot Emanation originating from the monster. Failure: The target has the Poisoned condition until the start of its next turn. Success: The target is immune to the Stench of all monsters for 1 hour.

The monster makes three Rend attacks.

Melee Weapon Attack: +7 to hit, reach 5 ft., one target. Hit: 15 (2d8+4) slashing damage plus 9 (2d8) poison damage.

The monster jumps up to 30 feet by spending 10 feet of movement.