Compsognathus Swarm (5e Creature)
From D&D Wiki
tiny swarm of Tiny beasts, unaligned
Blood Frenzy. The swarm has advantage on melee attack rolls against any creature that doesn't have all of 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 compsognathus. The swarm can't regain hit points or gain temporary hit points.
Bite. Melee Weapon Attack: +5 to hit, reach 0 ft., one creature 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.
Tiny dinosaurs that walk on two legs, the compsognathus only grow to the size of a turkey. These dinosaurs travel in swarms to fulfil their hunger for flesh and blood. Although a compsognathus is very weak individually, they are fearsome while in swarms as they tend to climb and overrun larger creatures while tearing off pieces of flesh with their bites.