McBain is the name of the fictional (within the Simpsons) character played by an actor named Ranier Wolfcastle. He appears in numerous episodes (he has the role of Radioactive Man in the movie also starring Milhouse van Houten).

Memorable quotes:
"My eyes! The goggles do nothing!" -- the Radioactive Man movie episode.
"Maria, my mighty heart is breaking!"
"My son returns from a fancy east coast college, and I'm horrified to find, he's a nerd.

Jay Sherman: "...Ranier Wolfcastle. Star of the reprehensible McBain movies."
Ranier Wolfcastle: "Jay, my new movie is a mixture of action, und comedy. It's called 'McBain: Let's get silly.' It's just me in front of a brick wall for an hour and a half. It cost eighty million dollars to make."
(movie clip)
Jay: "How do you sleep at night?"
Ranier: "On a big pile of money, surrounded by many beautiful ladies."
Jay: "Just asking!"