Pheromosa is an Ultra Beast that does not evolve. It ties with Mega Lucario Z for the highest base Speed among Fighting types, and Beast Balls carry a five times catch rate modifier against Ultra Beasts, meaning Pheromosa can never fail to be caught in Sun and Moon.
Pheromosa arrived in Alola through an Ultra Wormhole in the episode Beauty is Only Crystal Deep, attacking Trainers to steal their Z-Crystals and building up a collection. Meowth developed a crush on it and kept shielding it from the Ultra Guardians, until Bewear finally defeated it, allowing the team to catch it and return it home.
Pheromosa's first dated cards were an ultra rare and a secret rare GX in Ultra Prism, both illustrated by 5ban Graphics. SM Black Star promos also exist, illustrated by You Iribi and 5ban Graphics. Forbidden Light contributed a rare by Hitoshi Ariga, and Unbroken Bonds paired it with Buzzwole across four tag team GX cards illustrated by Mitsuhiro Arita, aky CG Works, and kirisAki. Hidden Fates Shiny Vault later added a shiny rare by Mizue.
An Ultra Prism ultra rare GX card illustrated by 5ban Graphics, among its first dated cards.
A Pheromosa & Buzzwole GX tag team card illustrated by Mitsuhiro Arita.
A Hidden Fates Shiny Vault shiny rare illustrated by Mizue.
No, Pheromosa does not evolve into or from any other Pokémon.
It arrives in Alola stealing Z-Crystals until Bewear defeats it in Beauty is Only Crystal Deep.

フェローチェ
Bug · Fighting
Pheromosa is an Ultra Beast, a Bug/Fighting type resembling a slender anthropomorphic insect with a crown-like head crest. Our catalog lists 10 Pheromosa cards across 5 sets, including Ultra Prism GX cards and Unbroken Bonds tag team cards shared with Buzzwole.