1. An enemy from Shining Force, for the Sega Genesis, part of the series of "Shining" series of fantasy console games developed by Sega.
2. Also could refer to any evil clown, although this particular name is generally used by fans of the original Shining Force game. As the word "dire" generally means "Warning of or having dreadful or terrible consequences," according to most dictionary whores, it seems perfectly appropriate.
Gamer: I just walked into a dark alley and fought a Dire Clown in hand-to-hand combat!
Friend: Oh? And when was the last time you left your bedroom, Mr. Gamersexual?