Super Mario Bros. - Glitch - Mushroom/Flower Shrink - Retro Game Clipping

This is a glitch in the original Super Mario Bros. game on Nintendo which makes Mario shrink instead of grow when he gets a mushroom or flower. In the World 1-4 castle, when you get to King Koopa you need to time the jump that allows you to open the bridge and get hit by the boss at the same time. You'll see in the video. Enjoy!