This adorable black swallowtail caterpillar may look harmless curled up around a piece of bark, but if you sneak up on the critter, it will unleash a surprisingly putrid counterattack. 

Hidden in the caterpillar’s head are two large, bright orange antenna or forked gland, called osmeterium. When agitated or in danger, the snake tongue-like gland shoots out towards the threat and emits a foul, spoiled cheese smell.

On the account NatureBrainz, two teachers in New Jersey posted this video of the black swallowtail caterpillar’s violent defense mechanism, poking the creature’s soft fluorescent green body. You can see the finger in the video immediately jump away in shock when the caterpillar’s body retracts and springs the forked gland forward.

There does not seem to be any pain if you are attacked by the insect, however people have reported that the chemical odor released is so strong that it can take several washes to rid of the stink.

Every day we track down a Video Wonder: an audiovisual offering that delights, inspires, and entertains. Have you encountered a video we should feature? Email