McBain, AKA Rainier Wolfcastle AKA "On closer inspection, zese are loafers" is one of those instantly recognisable but barely featured Simpsons characters who appears throughout the show without any real part (until he was Radioactive Man).
What you may not have known was that enough of the McBain film has been shown in clips throughout the shows run that they form their own mini-movie once they have stitched together. And thankfully College Humor has done that for us.
Via College Humor