Beaks

Melee Weapon Attack: +5 to hit, 0 ft., one creature, in the swarm's space. 21 (6d6) piercing damage or 10 (3d6) if the swarm has half its hp or fewer.

Toboggan Charge (Recharge 5-6)

The swarm moves up to 20' in a straight line over ice or snow and can move through the space of any Large or smaller creature. The first time it enters a creature's space during this move that creature must make a DC 14 Str save. On a failure a creature takes 10 (3d6) bludgeoning damage and 10 (3d6) piercing damage and is knocked prone. On a success a creature takes half the damage and isn't knocked prone.