Pack Tactics. The zombie monkey has advantage on an attack roll against a creature if at least one of the zombie monkey's allies is within 5 feet of the creature and the ally isn't incapacitated.

Undead Fortitude. If damage reduces the zombie monkey to 0 hit points, it must make a Constitution saving throw with a DC of 5 + the damage taken, unless the damage is radiant or from a critical hit. On a success, the zombie monkey drops to 1 hit point instead.

Bite. Melee Weapon Attack: +3 to hit, reach 5 ft., one target. Hit: 3 (1d4 + 1) piercing damage.

Claw/Slam. Melee Weapon Attack: +3 to hit, reach 5 ft., one target. Hit: 3 (1d4 + 1) bludgeoning or slashing damage (zombie monkey’s choice).