M.C Birthday is a rapper who works in the Ice cream parlour where Ned Flanders is taking the residents from Springfield Retirement Castle out for Jasper's birthday. When The Squeaky-Voiced Teen hears of Jasper's birthday he presses an alarm, prompting M.C Birthday and the Goodtime Gang to perform the following rap:

YO, YO, YO, Give it up for M.C Birthday I said a Birth, a Day, A Birth of the Day Now My good time gang will blow you away

At that cue the gang come out and dance. Jasper and the other old people are scared of this and Grandpa hides under the chair.

Based on M.C. Birthday's traffic-signal jewelry, he appears to be M.C. Safety, seen earlier as the leader of M.C. Safety and The Caution Crew .