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.

Web Walker. The web zombie ignores movement restrictions caused by webbing.

Action: Multiattack. The web zombie makes two slam attacks. If both attacks hit a Medium or smaller target, the target is restrained by webbing. As an action, the restrained target can make a DC 11 Strength check, bursting the webbing on a success. The webbing can also be attacked and destroyed (AC 10; hp 5; vulnerability to fire damage; immunity to bludgeoning, necrotic, poison, and psychic damage.)

Slam. Melee Weapon Attack: +3 to hit, reach 5 ft., one target. Hit: 4 (1d6 + 1) bludgeoning damage.