Cosmoem, the Protostar Pokémon, is a Psychic-type Legendary Pokémon introduced in Generation VII. It evolves from Cosmog and into either Solgaleo or Lunala depending on the game version. Resembling a dark blue orb encased in a golden shell, Cosmoem is surprisingly heavy, weighing 2204.4 lbs. (999.9 kg), due to its nature as condensed starlight. In the Alola region, Cosmoem is considered a gift from the heavens, and its weight is seen as a testament to its celestial origins. It plays a crucial role in the storyline of Sun and Moon versions, acting as a bridge between Cosmog and the legendary Pokémon Solgaleo and Lunala.
Cosmoem has characteristics of both a stylized sun and a stylized moon, having rays and a pair of crescents, respectively. Its enormous weight despite its extremely small size shares similarities with super-compressed astronomical bodies such as black holes and neutron stars. Given its description, it seems to be an embodiment of star formation in general.