FusionDex

Koffbat are disease-ridden creatures that fill the air with noxious fumes and drool thick, sticky saliva onto cavern floors. Many Pokémon that either inhale the fumes or touch the saliva break out in hives.

Its fangs easily puncture even thick animal hide. Getting up close to a Koffbat will give you a chance to observe, through its thin skin, the toxic gases swirling inside.