Bagon evolves once at level 30 into Shelgon and again at level 50 into Salamence. Through its evolution chain, Bagon keeps its dragon type, but with its final evolution, it gains the added type of flying.
Bagon's evolution chain also lets it learn new abilities once it has achieved its flying type, such as fly, which is useful to return to previously visited towns and is a powerful attack. From its evolution into Shelgon, the Pokémon's base stats increase at a fairly decent rate. However, once it evolves into Salamence, most of its base stats grow dramatically, especially two of the most important stats for dragon-type Pokémon, attack and speed.