Cottonee (Japanese: モンメン Monmen) is a dual-type Grass/Fairy Pokémon introduced in Generation V. Prior to Generation VI, it was a pure Grass-type Pokémon.
It evolves into Whimsicott when exposed to a Sun Stone.

Cottonee is a white, circular Pokémon. It has white, puffy sections on the top of its head and its underside. Behind it is a green, star-shaped section similar to the area where a plant connects to its produce. It has orange, oval-shaped eyes, and furled, notched leaves on the sides of its body.

Cottonee is blown around by the wind because of its lightweight composition. The only circumstance in which it cannot be blown by the wind is when it has been soaked by rain, which weighs it down and makes it soggy. Afterwards, this Pokémon will stay under a tree until it dries, so that it may be blown by the wind again. During the mating season, Cottonee blow in the wind in large groups. Its cotton can be used as a defensive mechanism that aids its self-defense. Cotttonee's cotton is used to manufacture top-quality pillows and beds that are soft, puffy, light, and airy. When Eldegoss's cotton is weaved together with Cottonee's, it makes a cloth that is popular with many luxury brands.
(The above content is from the bulbapedia.)