The Leaf ability grants Kirby the power to to create and control leaves. He can perform many far-reaching attacks, as well as a special guard that renders him impervious to all attacks, much like Tac's hiding guard in Kirby Super Star.
Kirby tosses a few leaves which swirl upwards at about 30 degrees in a broad spiral.
8 (1st hit), 7 (2nd, 3rd hits)
Hold button 1
Kirby spins in a twirl and can move about on the ground like Tornado with leaves spinning about him. The attack lasts as long as the button is held. This leads up to the Leaf Scatter attack.
12 (1st hit), 10 (repeat hits)
Leaf Swirl, then release button 1
The leaves spinning around Kirby now fan out in a wide radius, ending the Leaf Swirl. Kirby is invincible when the move is initiated.
Dash + hold button 1
Kirby dashes with a vortex of leaves surrounding him. This move is very similar to Tornado's basic attack, but it ends after a few seconds.
28 per hit (2 hits)
Kirby performs a special guard move by hiding in a green pile of leaves. This lasts as long as the button is held.
↑ + button 1
Kirby conjures up a column of large leaves in front of him. It has a very quick starting animation and reaches quite high vertically, making it useful on aerial enemies.
(midair) ↓ + button 1
Kirby throws five leaves downward and forward while in midair. This move can be executed in succession, and is useful for covering landing areas with enemies or dealing consistent damage to grounded bosses.
It's time to dance! The Leaf Dance creates a gorgeous swirl of razor-edged leaves. Press A to Guard, and...huh?! You're gone!
Be a leaf on the wind with this sharp ability. Spin up a torrent of dancing leaves to slice and dice, or activate your Guard and-- Hey, where'd you go?!
In Later Games
The Leaf ability reappears in Kirby: Triple Deluxe, and seems to function identically to its appearance in Kirby's Return to Dream Land.
The method that Leaf Kirby uses to attack enemies appears to be similar to the primary attack of Wood Man from Mega Man 2.
Leaf Kirby spins his leaves in a tornado-esque style. In the Pokémon series, an attack introduced in Generation V called Leaf Tornado is used in a similar way.