Ancient Winter Wolves

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

Pack Tactics. The Ancient Winter Wolf has advantage on attack rolls against a creature if at least one of thier allies is within 5 feet of the creature and the ally isn't incapacitated.

Trample. When the Ancient Winter Wolf enters any enemy's space for the first time on a turn, the enemy must succeed on a DC 14 Strength saving throw or be knocked prone.

Multiattack. The Ancient Winter Wolf makes one bite and one claw attack. 

Bite. Melee Weapon Attack: +6 to hit, reach 5 ft., one target. Hit: 14 (2d12 + 6) piercing damage. The target must make a DC 14 Str. saving throw or be knocked prone.

Claw. Melee Weapon Attack: +4 to hit, reach 5 ft., one target. Hit: 12 (2d10+2)

Cold Breath (Recharge 5-6). The Ancient Winter Wolf exhales a blast of freezing wind in a 15-foot cone. Each creature in that area must make a DC 14 Dexterity saving throw, taking 18 (4d8) cold damage on a failed save, or half as much damage on a successful one.