A mullet is a kind of fish. Mullet often jump out of water. In recent years, "mullet" also came to be a slang word for a hairstyle that is short at the front and top, and long at the back. This slang word is said to have been started by Mike D of the Beastie Boys in 1995, and after 2000 was spread by a small group of people in San Francisco through the Internet.