In the Pokmon video game series, Golbat is a Poison/Flying type Pokmon that can evolve into Crobat when exposed to high levels of friendship with its trainer during the night.
Evolving Golbat to Crobat is beneficial because Crobat has higher base stats, learns more powerful moves, and gains the valuable Flying type, which grants it immunity to Ground-type attacks and resistances to Bug-, Fighting-, and Grass-type attacks.