Joker-Mite was a character created exclusively for Batman: The Brave and the Bold.
History[]
When the Joker was given Bat-Mite's powers by accident, he awarded Bat-Mite by creating Joker-Mite, a miniature version of himself. Just as ruthless, when the Joker went into Batman's mind, Joker-Mite plotted to kill Batman, thus taking Joker down, too. With Joker out of the way, Joker-Mite planned to take over the gang. Bat-Mite and Harley Quinn defeated him. Once Bat-Mite got his powers back, he undid everything except Joker-Mite. At Batman's suggestion, Joker-Mite was taken against his will to the Fifth Dimension by Bat-Mite to serve as his arch-nemesis.