Shapechanger. The werewolf zombie can use its action to polymorph into a wolf-humanoid hybrid or into a wolf, or back into its true form, which is humanoid. Its statistics, other than its AC, are the same in each form. Any equipment it is wearing or carrying isn't transformed. It reverts to its true form if it dies.

Keen Hearing and Smell. The werewolf zombie has advantage on Wisdom (Perception) checks that rely on hearing or smell.

Undead Fortitude. If damage reduces the werewolf 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 werewolf zombie drops to 1 hit point instead.

Multiattack. (Humanoid or Hybrid Form Only). The werewolf zombie makes two attacks: two with its fists (humanoid form) or one with its bite and one with its claws (hybrid form).

Bite (Wolf or Hybrid Form Only). Melee Weapon Attack: +4 to hit, reach 5 ft., one target. Hit: 6 (1d8 + 2) piercing damage.

Claws. (Hybrid Form Only). Melee Weapon Attack: +4 to hit, reach 5 ft., one creature. Hit: 7 (2d4 + 2) slashing damage.

Fist. (Humanoid Form Only). Melee Weapon Attack: +4 to hit, reach 5 ft., one creature. Hit: 5 (1d6 + 2) bludgeoning damage.