Gag name

A gag name is a false name used to elicit humor through its simultaneous resemblance to a real name on the one hand, and to a term or phrase that is funny, strange, or vulgar on the other hand. The source of the humor is the pun and double entendre; frequently, the humor arises when an unknowing victim is induced to use the name without realizing the joke. Urban legend holds that such a prank is often played on substitute teachers or others who must read a roll, for whom pranksters will switch the roll with one containing such names.