Bubble

Bubble is One of Kirby's Copy abilities.

With this newer ability, Kirby gains a frilly cap adorned with bubbles, and a special bubble wand with which he can create even more bubbles to trap enemies in. It has so far only appeared in Kirby Squeak Squad, likely due to to it being the only game the copy palette has appeared in.

However, a similar Bubble ability has also appeared in the teaser trailer for the Kirby game on the Wii, though this has been confused with the anime exclusive ability, Water.

Kirby Squeak Squad
With the Bubble ability, Kirby is able to create ability bubbles out of enemies with copy abilities, and star bubbles out of enemies that don't have abilities. These bubbles are then stored in the Copy Palette, like the bubbles normally found in stages.

Its basic attack, which just fires a flurry of bubbles, is relatively weak but makes up for it with it's rapid firing rate. But after acquiring the Copy Scroll, Kirby can fire a single large bubble, which can defeat most enemies in one hit.

Trivia
The hat Bubble Kirby wears is actually a type worn mainly by kids during bath time to keep soap out of their eyes when they get their hair washed. (It might only be common to Japan.) Of course, Kirby doesn't have any hair to wash...