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

Pack Tactics. The wolf has advantage on an attack roll against a creature if at least one of the wolf's allies is within 5 feet of the creature and the ally isn't incapacitated.

Incorporeal Movement. The wolf can move through other creatures and objects as if they were difficult terrain. It takes 5 (1d10) force damage if it ends its turn inside an object.

Bite. Melee Weapon Attack: +7 to hit, reach 5 ft., one target. Hit: 12 (2d6 + 5) piercing damage. If the target is a creature, it must succeed on a DC 13 Strength saving throw or be knocked prone.

Terrifying Howl (Recharge 5-6). The wolf emits a terrible howl audible within 150 feet. Creatures within 30 feet of the wolf must succeed on a DC 12 Wisdom saving throw or become stunned until the end of the wolf’s next turn.