Undead Fortitude. If damage reduces the Zombie Giant Ape 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 drops to 1 hit point instead.

Multiattack. The ape makes two fist attacks.

Fist. Melee Weapon Attack: +9 to hit, reach 10 ft., one target. Hit: 22 (3d10 + 6) bludgeoning damage.

Rock. Ranged Weapon Attack: +9 to hit, range 50/100 ft., one target. Hit: 30 (7d6 + 6) bludgeoning damage.

The Zombie Giant Ape can take 2 legendary actions, choosing from the options below. Only one legendary action option can be used at a time and only at the end of another creature's turn. The Zombie Giant Ape regains spent legendary actions at the start of its turn.

Detect. The Zombie Giant Ape makes a Wisdom (Perception) check.

Fist smash (Costs 2 Actions). The Zombie Giant Ape makes one Fist attack.