Arch-Wolf

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.

Cleave. When the wolf's attack reduces an undamaged creature to 0 hit points, any excess damage from that attack might carry over to another creature nearby. The wolf targets another creature within reach and, if the original attack roll can hit it, applies any remaining damage to it. If that creature was undamaged and is likewise reduced to 0 hit points, repeat this process, carrying over the remaining damage until there are no valid targets, or until the damage carried over fails to reduce an undamaged creature to 0 hit points.

Multiattack. The wolf makes two bite attacks.

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 15 Strength saving throw or be knocked prone.

These attacks count as magical for the purpose of overcoming resistance and immunity to nonmagical attacks and damage.