Crouching is a ground-based position achieved by holding down on the control stick when you're standing on a surfce on which you can stand.
Doing this will make certain characters who have low crouches, like Jigglypuff, impossible to grab, and many high attacks will miss. It will also activate crouch cancelling should someone attack you while you are crouching.
Low crouches include:
- Jigglypuff
- Kirby
- Pichu
- Sheik
- Mario, Doctor Mario, and Luigi