His "Frame Up" character
When Homer and Marge appeared on Frame Up and Myrna Bellamy's murder was staged, the Man with Braces "stole" her necklace and made sure that Marge and Homer saw him leaving the house with it. This made Marge and Homer, who were already the prime suspects, look even more guilty because they were accusing a mysterious third party of the crime ("It was the man with the braces!") without having any evidence to back them up.
He predented to be a murderer on Frame Up, a hidden camera prank show but just as Homer was be-ing accused of murder and put on the chair it was revealed he was just an actor. Carmen Electra also starred in it.