Mystery Tileswap Glitch!?
Back in 2005 while playing Super Mario All-Stars (SNES) I ran into a strange glitch in Super Mario Bros. 2 where it appeared as though the tiles used to display the graphics were randomly scrambled. I managed to get two screen-shots but unfortunately no video footage. I have never recreated this glitch nor seen it anywhere else, it's a total mystery!
UPDATE: Speedrunner Producks helped me out on this one.
"...You have to game over in 4-3, then get back to 4-3 and it should always look like this. I found the same glitch in the lost level(sic) in 9-3, you game over in the level and continue and you should end up getting a similar bug"
So there you have it, mystery solved!