Yo-yo is a Copy Ability that Kirby can obtain in Kirby Super Star and its remake. Kirby must inhale and swallow Gim to obtain it. When Kirby becomes a Yo-yo trick-master he wears a backwards light blue cap (differentiating from the Wheel ability's red cap) and wields a typical red and white Yo-yo as his weapon.
Kirby combines break dance moves with yo-yo tricks as means of attack with this ability. His basic attack involves throwing his yo-yo as a projectile in any direction. This isn't all he can do with it, though- he can also grab his enemies with his yo-yo and drop them to deal huge damage, or use his yo-yo to do a showy spin jump. In a pinch, he can retreat or move forwards with a Break Spin. This ability's Break Spin was later used as Kirby's new dash attack in Super Smash Bros. Brawl, replacing his Burning-inspired attack.
Kirby throws his Yo-yo out which damages any enemy who comes into contact.
Up + B
Kirby throws his Yo-yo in a small arch upwards, damaging any enemy who comes into contact with it.
Down + B
Kirby throws his Yo-yo in a small arch downwards, damaging any enemy who comes into contact with it.
Dash + B
Kirby spins on his head while dashing forward. If done in the air, Kirby has more momentum and does slightly more damage.
10 (grounded), 12 (aerial)
Forward/Up/Down + B (Near enemy)
Kirby grabs enemies or mid-bosses (the latter only when defeated), and drops them hard enough to destroy them.
Down + (Up + B together)
Kirby spins around in the air, using his Yo-Yo as a weapon, and damages any enemies that come in contact with him. After the move, he is left vulnerable. At the highest point of his attack, the two stars that spin with him go opposite directions, and have the range to hit both Twin Woods if used in the center.
The Yo-yo, the ability cap, and the background of the ability picture are all direct references to Earthbound. The background depicts Earthbound's menu screen, and the Yo-yo and ability cap come from Ness, who wears a remarkably similar cap and often uses a yo-yo as a weapon. This can be seen as HAL referencing one of its own games because Earthbound is a series that was also made by HAL.
When Kirby inhales Ness in the Super Smash Bros. games, he wears Ness's sideways hat backwards, as if it was the Yo-yo hat. Both characters are also voiced by Makiko Ohmoto.
Yo-yo Kirby's hat is the same as those of Paint and Wheel Kirby's hats, but in a different color (Paint's is gray, Wheel's is red).
The Break Spin is Kirby's Dash attack in Super Smash Bros. Brawl.