"Oh...cool!" Willow is of course, instantly upon it, watching as it does it's thing. "Obviously highly corrosive, is it air contact that does it? No, that's not right, cause then every time you breathe you'd be burning a hole in your throat." She picks up a stick and pokes the bubbling acid, delight on her face as the stick melts away. "I bet it's held in two different sacks, and the act of spitting mixes them together, resulting in an acidic mix. Man, evolution really had to stretch for that one!"