Whimsicott is a small, brown, bipedal Pokémon. A mane of cotton-like fluff covers its back, neck, and forehead. Behind it is a green, star-shaped section similar to where a stem or vine meets a fruit or flower on a plant. Whimsicott's face features orange, oval-shaped eyes and its face is flanked by a pair of green-colored lobes shaped like curled horns or ears.
Whimsicott can manipulate its body to pass through cracks, no matter how narrow. It takes advantage of this ability as a notorious prankster, moving things and leaving cotton balls behind. However, should it get wet, it will be too heavy to move and answer for its pranks. Despite weighing 14.6 lbs (6.6 kg), Whimsicott appears capable of "riding upon the wind" but whether this means they actually generate whirlwinds themselves or get carried by wind currents remains unclear. Whimsicott likes to spend time in the sunlight in order to grow its cotton, though it will tear off and scatter the cotton should it start to build up too much.