Swarm of Poisonous Snakes 2014
CR 2 beast
Medium beast, unaligned
The swarm can occupy another creature's space and vice versa, and the swarm can move through any opening large enough for a Tiny snake. The swarm can't regain hit points or gain temporary hit points.
Actions
Melee Weapon Attack: +6 to hit, reach 0 ft., one creature in the swarm's space. Hit: 7 (2d6) piercing damage, or 3 (1d6) piercing damage if the swarm has half of its hit points or fewer. The target must make a DC 10 Constitution saving throw, taking 14 (4d6) poison damage on a failed save, or half as much damage on a successful one.
Environments: Caves, Desert, Forest or Jungle, Grassland or Plains, Hills, Mountain, Ocean, Ruins, Sewer, Swamp or Marsh, Tomb
Other versions
Source: System Reference Document 5.1 (Wizards of the Coast) · License: Creative Commons Attribution 4.0 / OPEN GAME LICENSE Version 1.0a details