I remember seeing this one Capcom Vs Snk 2 combo video that had a short clip of Mario at the end. It showed him in Mario Bros. 2. He picked up a radish and threw it at an enemy, and continued to use the same radish throughout the level by jumping on it and keeping it airborne!
There was another I heard about, this one pertaining to Mario Bros. 1. Mario had positioned three koopas under a block, and managed to wedge himself between the two, doing extremely fast jumps, while racking up the points.
Has anyone seen these videos, or ones similar to them? I can't find them anymore; any links would be appreciated!