Jigglypuff's Rest (Input: Down B) is a core part of her gameplan. It is her strongest kill move, being a high risk high reward move. If landed it is nearly unpunishable. In fact, there are many combos and confirms for rest, and profession jigglypuff players always strive to find more at various percents. When combined with her insane aerial presence and shield pressure, this move can be devastating and lead to stocks being taken in seconds. It has been this way since Super Smash Brothers Melee, and while Jigglypuff is now a low tier, that does not change the fact that rest is a good move that most characters would benefit from having.
DON'T REST ON THE REST