One that comes to mind is a 1960's Roger Ramjet episode where Roger's fans have forgotten about him in favor of Rabbit Man and Bunny Boy. Roger and his side kick end up hopping down the road in silly rabbit costumes while a piano plays a tune similar to the na na na na Batman! theme.

The British comic Spike Milligan had a loony skit where he opens a box at a department store to reveal a scrawny old man in a crappy batman outfit playing the banjo. "its a bird ... its a plane... Its Baaatmaaan!"
"Did I WRITE this???", asks Spike then walks off, possibly to take his bipolar meds.

and YOU?