Undead Fortitude. If damage reduces the zombie 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: Zombie Ogre can make two Morningstar attacks.

Morningstar. Melee Weapon Attack: +6 to hit, reach 5 ft., one target. Hit: 9 (1d8 + 4) piercing damage.

Putrid Stench: Any creature ending it's turn within 10ft of the Zombie Ogre must make a DC 13 Con save, or take 1d8 poison damage. (Passive Aura)

Flesh Scoop: On an enemy movement, Zombie Ogre scoops a mound of flesh from it's body and flings it at the moving creature. Ranged weapon attack: +5 to Hit, 1d8 +4 necrotic damage.

Zombie Ogre can take 3 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. Zombie Ogre regains spent legendary actions at the beginning of its turn.

"Stumble.." The zombie ogre falls, any creature in a 20ft radius must make a DC 13 Dex saving throw, taking 11 (2d10) force damage and become prone on a failed save, taking half damage on a successful and stay on their feet.

"Maul.." The zombie ogre sweeps up a nearby creature, forcing a strength contest to grapple and then performs a bite. +6 to hit, 10 (1d10+4) damage.