Sleep

Sleeping is a status ailment in the Mario role-playing games.

Super Mario RPG: Legend of the Seven Stars
In Super Mario RPG: Legend of the Seven Stars, sleep is one of the more common status ailments that the player can have. A physical attack will wake a character from sleep, but a magical attack will not. While sleeping, a character is completely immobile and helpless. Additionally, Princess Toadstool is able to afflict this condition on enemies.

Paper Mario
The afflicted will fall asleep, preventing them from moving for a few turns. Unlike in Super Mario RPG: Legend of the Seven Stars, the character cannot be woken up until the effect wears off.

Paper Mario: The Thousand-Year Door
In this game, the afflicted will fall asleep, but when attacked, there is a chance that they will wake up. This is indicated by a small exclamation point over the character when they are attacked. Its icon is a Sleepy Sheep. A number by the Sleepy Sheep indicates how long the victim will be asleep for.

Super Paper Mario
In Super Paper Mario, if the player is attacked by a Cherbil, a Crazee Dayzee, or an Amazy Dayzee, they will fall asleep, and they will have to wake up by shaking the Wii Remote until the on-screen meter is filled up, lest the player get attacked by an enemy. Also, the player can make enemies sleep by using a Sleepy Sheep. In the Underchomp battle, the player can use Piccolo to temporarily make it go to sleep (this is based on Cerberus' weakness of falling asleep when music is played in Greek mythology). When Mario sleeps in the game, Tippi or Tiptron will sit down on the player's head like a butterfly.

Super Smash Bros. series
Characters can go to sleep (the status effect here known as Asleep) in the Super Smash Bros. games by Luigi and Peach's Final Smash, Jigglypuff's Sing attack, and Bellossom's attack. This leaves them vulnerable for opponents to attack them.

Trivia

 * In Super Mario 64, Super Mario Sunshine, Super Mario Galaxy, and Super Mario Galaxy 2, if Mario is left alone and does not move for a while, he will sit/lay down and go to sleep. Mario and his partner or Pixl will also fall asleep in a similar manner in Paper Mario: The Thousand-Year Door and Super Paper Mario, although they will sleep standing. Luigi can cause Mario to sleep by telling him one of his overly long stories, and Merlumina can cause Mario to fall asleep by rambling on and on about her life.
 * Also in Super Mario 64, if Mario is left asleep for a while, he will dream about pasta.