Blood Frenzy. The swarm has advantage on melee attack rolls against any creature that doesn't have all its hit points.
Swarm. The swarm can occupy another creature's space and vice versa, and the swarm can move through any opening large enough for a Tiny quipper. The swarm can't regain hit points or gain temporary hit points.
Water Breathing. The swarm can breathe only underwater
Bites. Melee Weapon Attack: +5 to hit, reach 0 ft., one target in the swarm's space. Hit: 14 4d6 piercing damage, or 7 2d6 piercing damage if the swarm has half of its hit points or fewer.