Quoted By:
Type: Poison
70 BP, 95 Accuracy
Physical
Target loses 1/8 of their maximum HP after taking damage. If the attack breaks a substitute or hits Protect, the effect damage still occurs. If it misses, it does nothing.
Basically like spitting an acid at something, whick then becomes a vapor on contact and burns the surrounding area, which is why it causes some damage despite protect. Gives Poison types a decent stab that can help them break through walls and sashes, despite being a middling-BP move.
It's physical so that Drapion can use it but Gengar can't.