Tough Hide. +1 bonus to AC while in wolf or hybrid form (from natural armor).

Shapechanger. The frost giant werewolf can use its action to polymorph into a wolf-giant hybrid or into a huge wolf, or back into its true form, which is giant. 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 frost giant werewolf has advantage on Wisdom (Perception) checks that rely on hearing or smell.

Multiattack (giant or hybrid form only). The giant makes two greataxe attacks.
Greataxe. Melee Weapon Attack: +9 to hit, reach 10 ft., one target. Hit: 25 (3d12 + 6) slashing damage.
Rock. Ranged Weapon Attack: +9 to hit, range 60/240 ft., one target. Hit: 28 (4d10 + 6) bludgeoning damage.

Bite (Wolf or Hybrid Form Only). Melee Weapon Attack: +9 to hit, reach 10 ft., one target. Hit: 17 (2d10 + 6) piercing damage. If the target is a giant or humanoid, it must succeed on a DC 12 Constitution saving throw or be cursed with werewolf lycanthropy.

Claws (Hybrid Form Only). Melee Weapon Attack: +9 to hit, reach 10 ft., one creature. Hit: 13 (2d6 + 6) slashing damage.