Belching Gasper (5e Creature)
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Small monstrosity, unaligned
Spider Climb. The belching gasper can climb difficult surfaces, including upside down on ceilings, without needing to make an ability check.
Wormbrain Host. The belching gasper can't be compelled to act in a manner contrary to its nature.
Belch. The gasper emits a 15-foot cone of poisonous gas. Each creature that area must succeed on a DC 12 Constitution saving throw or take 7 (1d10 + 2) poison damaged and become poisoned for 1 minute. An affected creature can repeat the saving throw at the end of each of its turns, ending the effect on itself on a success.
Bite. Melee Weapon Attack: +1 to hit, reach 5 ft., one target. Hit: 4 (2d4 - 1) slashing damage.
Although the belching gasper has a drably colored, pathetic host body which is more than content to graze on moss or lichens, the symbiotic worm which lives inside it is garishly colored, a warning sign to potential threats of the debilitating neurotoxin it spews. Unlike other creatures in the gasper family, it survives perfectly well off of a herbivorous diet and generally only supplements it with meat from carcasses it may find. Once spurred to combat, however, it takes pleasure in observing the effects of its poison, and is usually convinced that its poison is the "best" of its kind.