after a while of walking through the forest, you find a maybe pokemon that you never saw before, you didn't even see it in the pokedex, it's like a Dragon Turtle, it looks powerful so you decide to face it in a battle, it mocks you since it thinks that you are weak and then it tells you that it's not a Pokemon but you don't believe it and you start a battle anyway, you surprisingly win with your Blastoise and you throw a pokeball to the pokemon and you catch it, after healing it, you open the pokeball and it comes out but it doesn't seem as self-centered as before, it seems that the pokeball really turned it into a partner Pokemon until now it considers itself one

Gwah! I don't like this being your pokemon, kiddo...