Even Steve-O might have thought twice before swallowing a live catfish. Unlike the harmless goldfish, Corydoras aeneus, also known as the “Cory” catfish, is armored with strong, overlapping scales. And it shares a famous defense mechanism with almost all of its catfish cousins: spine-like barbs embedded within each fin. When the fish is distressed, these barbs straighten and lock into place, turning the animal from a tropical pet into a sort of aquatic shuriken.

When the man arrived at the hospital, all he was able to tell doctors through the drugs and alcohol was that he was having trouble swallowing, according to Linda Benoist, an Erasmus otorhinolaryngology resident who treated him. It wasn’t until the doctors spotted a fin in his throat that he could recall more specifically what had happened.