brock how the HELL did you become a gym leader
That’s why he’s the first one.
To be fair, form changes would come in a later generation and that could be considered “a metamorphosis attack.”
Also, Koga was playing dirty pool, anyway. How the hell do you just have your Pokémon SPONTANEOUSLY evolve? At least when Krabby evolved into Kingler in the middle of a battle, he had JUST defeated another Pokémon.