What the shell

"What the shell" is a phrase used in some versions of Teenage Mutant Ninja Turtles, and especially by the of the 2003 TV series. The phrase is a of "what the hell," replacing the mildly vulgar word "hell" with the word "shell" as a  in reference to turtle shells. Other phrases are also possible wherever "the hell" would otherwise be used as an intensifying phrase, including "how the shell," "when the shell," "where the shell," "who the shell" and "why the shell."