Swablu is an avian Pokémon with a round, blue body. Since it has no discernible neck, its body appears to be all head. There are two long feathers on top of its head, and it has a short, rounded white beak and beady, black eyes. Its wings are fluffy and white, resembling cotton or clouds. It has tiny, white feet and two pointed tail feathers.
Swablu does not like dirty surroundings, so it cleans things with its cottony wings. It uses streams and freshwater springs to wash its wings when they become dirty from polishing. It is commonly found living in flocks in forested habitats, but often flies closer to towns during the spring. Swablu is very friendly and largely unafraid of humans. As a result, it frequently perches on people's heads like a fluffy hat.
Multiple Swablu made their main series debut in True Blue Swablu, where it played a major role. One of them got separated from its flock when the tree its flock was nesting in was struck by lightning. May helped take care of Swablu, who had injured its wing, but the Pokémon was suddenly afraid to fly. After the wing was healed, it took Ash and his friends some time to help Swablu get the courage to fly again. At the end of the episode, May offered Swablu a place on her team, but ultimately chose to let it go when its flock returned.
Multiple Swablu appeared in the Hoopa's Surprise Ring Adventures short Flying in the Air. They were among the immense Flying-type Pokémon summoned by Hoopa to create wind for Ash and Pikachu, but their combined Gust was too much for them and sent them blasting off.
Swablu is based on a bluebird combined with cotton or a cloud. It also shares traits more specifically with the ultramarine lorikeet. Behaviorally, it is similar to the grey jay in that they are both given to sitting on people's heads.
Swablu may be a combination of swab (referring to its cotton swab-like wings) and blue. Swa may also derive from swallow, a type of bird.
Tyltto may refer to Tyl—also known as Epsilon Draconis—a star in the constellation Draco, the Dragon. It may also be a reference to the play L'Oiseau Bleu (The Blue Bird) by Belgian playwright Maurice Maeterlinck. The story is about two siblings, Mytyl and Tyltyl (ミチル Michiru and チルチル Chiruchiru in the Japanese translation of the play), who are tasked with finding the "blue bird of happiness."