Mellogon, the Meek Pokemon

Dwargon, the Pint-Sized Pokemon, is a tiny Dragon-type Pokemon at risk of being snatched up by bird Pokemon. To chase away predators and survive in the wild, Dwargon adopted a nasty, belligerent attitude that surprises even the toughest Pokemon. Some trainers have told stories of climbing up a tree to escape a Dwargon they accidentally stumbled upon.

If a trainer cares for their Dwargon, it may evolve into Mellogon, the Meek Pokemon. During evolution, its foul attitude completely flipped, and now Mellogon is cowardly and can't assert itself. As a Dwargon, it rarely participated in actual battles by chasing away predators with sheer determination. Now that it has the power to defend itself, Mellogon is inexperienced in battle and shies away from conflict. Mellogon would much rather laze about at home than engage in battle.