That's why Little Billy you can never play in the streets you can get yourself killed or... (Mario runs him over)
|—Guy to Little Billy|
Guy is always nervous about Little Billy and always attempts to tell him not to play on the street; it also fails every time by getting run over by Mario. Little Billy doesn't like Guy and just speaks in profanities saying things like "Dafuq?" and "Surprise mother f*cker".
In "Mario Goes Shopping", Guy tried to tell Little Billy not to play on the street (as he could get killed), but was then run over by Mario, the latter arriving at Wal-Mart. The duo later appeared at the near end of the video when Guy (now without his legs) shouted at Billy, "YOU COULD GET YOURSELF KILLED ON HERE!" when he was run over by Mario again. After this Billy said "SURPRISE MOTHERF**ER".
In "Mario for Hire.", it was pretty much the same, except in a different place and it only happened once. After Mario runs over Guy, the kart was then flying in the sky, with Mario (wearing sunglasses) and a dying Guy on board.
In "SMG4 Movie: 10 Year Anniversary Special" It was pretty in the same, execpt in a different place and it also happened once again.
The two had differing looks over the months between "Mario Goes Shopping", "Mario for Hire" and "SMG4 Movie: 10 Year Anniversary Special". In the former, Guy and Little Billy looked exactly like X and Baby Luigi, respectively. In later, they looked like Jasslam and Baby Mario this time, In SMG4's 10th Anniversary special, they looked like a Carl Wheezer from Jimmy Neutron and baby.(again, respectively).