What's with South Park co-creators Trey Parker and Matt Stone and their seeming preoccupation with mentally retarded people?

Around this time last year, The New York Observer reported that the mischievous duo had backed a Daily Show-type pilot featuring reporters with various developmental disabilities. Now they're introducing a new character on South Park, Timmy, who is mentally retarded and in a wheelchair.

"Some people will misconstrue him, but we really do have a point to make with him," Parker told London's Daily Star while promoting the DVD release of South Park: Bigger, Longer & Uncut in the UK. "He's happy to be him. That's what's so cool about him."

Timmy, who made his debut on Comedy Central in a cameo during last night's episode, will soon become a major character on the show. An episode is already in the works with Timmy as the central figure.

Parker and Stone, who recently showed up at the Academy Awards dressed in evening gowns, are known for thumbing their noses at societal conventions. A Comedy Central spokeswoman says the duo just want to portray Timmy as part of the gang and not as the subject of cruel schoolyard humor. "They have very good intentions for Timmy," she tells TV Guide Online. "Timmy just happens to be in a wheelchair and screams his name every time he hears it. It's very funny."