Sleep

Sleep is maybe the most useless one of Kirby's copy abilities. When copied, Kirby instantly falls asleep and can't do nothing before he wakes up, which takes around five seconds. During this time, Kirby is open for attacking.

Sleep appears in Kirby: Right Back at Ya! only in episode 16, Flower Power. King Dedede tricks Kirby to Inhale Noddy and Kirby falls asleep. In anime, the Sleep Kirby is rather different than in games. It was supposed to make Kirby sleep for 100 years. He would only wake up if he smelled the scent of legendary Pyukii Flower.

Features
In all games, Kirby just instantly starts sleeping and loses the ability once he wakes up, nothing special about that.

However, with Copy Scroll in Kirby: Squeak Squad, Sleep Kirby gets an interesting new ability. He restores some hitpoints while sleeping. It doesn't restore very many hitpoints, but can provide first aid when in critical situation.