Pants On The Ground. You know something is up when Simon can't be heard over the other judges' laughter.
Of course, Pants On The Ground also PROVES the producers are deliberately monkeying with the screening process to ensure plenty of this kind of thing for the program. Pants was a BLATANT invocation of this Trope; the guy was 62 and should have been turned away at the door, but they let him through to the actual taped auditions. The only way in hell that could happen is if they planned this from the start...
Before Pants on the Ground, there was I Am Your Brother.
And then there's Nick Mitchell's (aka. Norman Gentle's) performance of And I Am Telling You I'm Not Going, essentially a deliberately campy, So Bad, It's Good parody of the whole competition.
Renaldo Lapuz's original song, "I Am Your Brother". Combined with his outfit... Then came the season finale, when he performed with a marching band...