German police say a teenager's attempt to frighten a group of young people by wearing a clown mask and brandishing a hammer on a Berlin street turned out very badly.

Berlin police said Tuesday that a 14-year-old responded by pulling a knife and stabbing the clown, only to find that the clown was a 16-year-old acquaintance.

He rendered first aid until emergency medical help could arrive Monday.

The older teen was taken to a hospital. The 14-year-old was released to his parents.

News media in Europe and America have reported a rash of sightings — some confirmed, some not — of people dressed as clowns and acting in a disturbing manner.

The U.S. Halloween observance, which involves scary costumes and has become more popular in Europe, is Monday, Oct. 31.