Combining the style of Heath Ledger's Joker with the taste in art of Jack Nicholson's, a mysterious figure is making enemies of the street artists of Tehran.

Known only as the Joker, he defaces graffiti and stencil art throughout the city, using red spray paint to leave behind the trademark smile and a simple scrawled signature. According to ABC News correspondent Muhammad Lila, the real mystery may not be the Joker's identity but rather how he moves so quickly: He manages to deface new graffiti before typically prompt city workers can find and paint over it.