M.C. Safety and the Caution Crew
From the "Bart vs. Lisa vs. the 3rd Grade" episode of The Simpsons (17 Nov. 2002).
An old-school style rapper so lame that not only does he rap about crosswalks and juice at grade school assemblies, AND get only about 30 seconds to perform, he still puts a period after the "M" and the "C" in "MC." Amazingly, he's an African-American, though the other three members of the crew are white.