Rest

Rest is the name given to Jigglypuff's Down Special Move. Jigglypuff turns toward the camera and falls asleep for several seconds. Before Jigglypuff falls asleep, any opponent in contact with it is instantly hit. This attack is known for having high knockback, no startup lag, very small range, and a long vulnerability period. However, Jigglypuff gains invincibility frames for approximately the time it takes to close its eyes.
 * The move varies from game to game, with Melee's Rest having several times more knockback and 8% more damage at the expense of a bit of range. In Super Smash Bros. Brawl, Jigglypuff's Rest deals less initial damage and knockback, only gives vertical knockback, and it no longer has a fiery effect and instead produces a flower effect. However, it is still a powerful KOing move. In Super Smash Bros for the N64, Rest is very similar to melee's rest, having very high killing power.
 * Initial damage = 15%, flower damage = 7-15% (when in brawl). Flower damage is potentially 30% if the enemy stands still, meaning that it has a possible total damage of 45%.
 * Because of the reduced knockback in Brawl, it cannot KO at as low percents as it could in Melee, but because it only gives vertical knockback it guarantees a star KO if it KOs the opponent. This eliminates most of the attack's vulnerability due to the amount of time it takes an opponent to KO off the top giving Jigglypuff time to wake up.
 * The attack can be combo'd into by many of Jigglypuff's moves, including up throw, pound, and up tilt. The hitbox comes out in one frame, making it tied for the fastest move in the series with the Reflector move.
 * If Jigglypuff uses Rest over water, it will wake up as soon as it lands in the water.
 * The invincibility frames also allow Jigglypuff to rest explosive items, and catch opponents in the blast, without taking any damage or knockback. It also means that some Final Smashes can be avoided such as Cook Kirby, Critical Hit and Triforce Slash.
 * Rest is not a Home-run Bat alternative in Brawl ' s Home-run Contest as it was in Melee. In Brawl it has no horizontal knockback and flower damage doesn't apply to Sandbag.
 * If sitting on top of Porky, Jigglypuff can use rest on him and deal a large amount of damage to him (about the same as the Home-run Bat).
 * If Rest is used in Fountain of Dreams on the water, Jigglypuff's eyes will still be open, but only in the waters reflection.
 * If viewed in the magnifying glass, Jigglypuff's eyes will be open.
 * If Rest is countered by Roy or Marth, Jigglypuff will not be hit by the return attack.

Origin
The Smash Bros. version of Rest is completely different from the Pokémon version. In Pokémon, Rest dealt no damage at all, instead, it put the user to sleep for two turns in exchange for the user gaining all of it's HP back, and healing any status ailments. This is another example of the Smash producers changing the function of moves to suit the games. Other examples include Withdraw and Double Team.