Army of Farting Hamsters

Stench. The army is constantly farting. Any creature other than an army of farting hamsters that starts its turn within 5 feet of the army must succeed on a DC 15 Constitution saving throw or be poisoned until the start of the creature's next turn. On a successful saving throw, the creature is immune to the stench of all armies of farting hamsters for 1 hour.

Swarm. The army can occupy another creature's space and vice versa, and the army can move through any opening large enough for a tiny hamster. The army can't regain hit points or gain temporary hit points.

Multiattack. The army makes one attack with it's bites and one attack with it's blasting horns.

Bites. Melee Weapon Attack: +5 to hit, reach 0 ft., one target. Hit: 20 (4d8+2) piercing damage, or 11 (2d8+2) piercing damage if the army has half of its hit points or fewer.

Blasting Horns. The army releases a large quantity of methane. All creatures within 30 ft. must succeed on a DC 15 Constitution saving throw or take 13 (3d8) poison damage. On a success, a creature takes half damage.