Halloween 1993. Kurt Cobain, the most visible face of grunge and the man who redefined alternative rock, decides to dress up as Barney, the purple dinosaur who at the time was taking over children’s TV screens all across the United States.

He didn’t stop at the costume. He put it on to play guitar at a party, posed for cameras backstage still wearing the suit, and in a gesture that sums up his razor-sharp humor, bared his backside to the lens without taking off the dinosaur head.

More than 30 years later, those photos are still circulating as one of the most unexpected snapshots of his career. There is no rockstar pose or calculated gesture: just a guy who decided to laugh at everything, including himself, in a year that would end up being the second-to-last of his life.

