"We won't pay because this guy is a... mook."
"But I didn't say nothin."
"We don't pay mooks!"
"A mook. I'm a mook... What's a mook?
"You can't call me a mook!"
A fight then ensues.
An insignificant or contemptible person.
"mook." The American Heritage® Dictionary of the English Language, Fourth Edition. Houghton Mifflin Company, 2004. 17 Jul. 2009.
The concept of mooks is used in many action movies (particularly in kung-fu) and beat-em-up arcade games, where the hero(es) cut through wave after wave of enemies easily (these being mooks) until they reach the boss of the scene, who despite being possibly weaker-looking than the mooks, is usually much more powerful/elusive.