Urban legend about a disgruntled fast food employee who had AIDS. He was said to have injected his blood into warm hamburger patties to incubate the virus with the intent of infecting random burger joint patrons with HIV.
Recently popularized by a South Park episode in which Jimmy Buffett did an AIDS benefit concert for little Eric Cartman. The episode actually made no mention of the urban legend, but used the term in a parody of a well known Jimmy Buffett tune.
"AIDS burger in paradise" -Jimmy Buffett from South Park Season 12, Episode 1.