It's being called "the worst Wheel Of Fortune answer of all time." The rules of the long-running game show are a fairly straight forward; it's basically Hangman. Contestants guess different letters until they can figure out the word or phrase, but the contestant in this video was apparently trying to change the phrase.
The category was "song lyric," and Stephen had all but five letters of the famous Jan and Dean lyric "Surf City, here we come." Only he guessed, "Surf clay where we go."
While that may be the worst guess in the show's history, Stephen is not the worst contestant. That has to be Indiana student, Julian Batts, who blew his chance at a million dollar prize.