Scientists have discovered that they’ve been overlooking something very important about two frogs native to Brazil. Namely, that they can stab enemies with venomous spines hidden on their skulls. 

Plenty of frogs are poisonous, meaning that coming into contact with their skin is toxic. But Corythomantis greeningi and Aparasphenodon brunoi are the first frogs discovered to be venomous, meaning that they inject a poisonous substance as a defense or attack method, the way a biting snake or stinging bee does.

Image Credit: Carlos Jared/Butantan Institute

The frogs’ venom, injected via a series of bony spines located across the skull, is described in a study in Current Biology. A. brunoi uses extremely toxic venom to defend itself—a gram of it, while less than what one would normally be exposed to in a single prick, could kill 80 humans. C. grenningi frogs are a little less poisonous, as researcher Carlos Jared found out when he was pricked by one, sparking the initial discovery.

[h/t: The Washington Post]