Snake, Swarm of Poisonous Snakes

Poisonous Swarm. The hissing, spitting, and constant nipping of snakes in the swarm leaves the swarm's space dripping with poison. A creature that starts its turn in the swarm's space must succeed on a DC 14 CON save or be poisoned until the start of its next turn.

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 snake. The swarm can't regain HP or gain temporary HP.

Swarm Resilience. The swarm is resistant to bludgeoning, piercing, and slashing damage, and it is immune to the charmed, frightened, grappled, paralyzed, petrified, prone, restrained, and stunned conditions.

Bites. _Melee Weapon Attack:_ +6 to hit, reach 0 ft., one creature in the swarm's space. _Hit:_ 10 (4d4) piercing damage, or 5 (2d4) piercing damage if the swarm has half of its HP or fewer. The target must make a DC 14 CON save, taking 18 (4d8) poison damage on a failed save, or half as much damage on a successful one.