Gyarados
Gyarados naturally looks grumpy. It is one of the most uncontrollable and destructive Pokémon, judging by its Pokédex entries. The entry in Pokémon Scarlet sums up nicely what a hothead Gyarados is:
When it appears, it wreaks havoc. It only calms down once it has destroyed everything around it.
Other entries add that it destroys entire villages, cities, mountains, and fields. The rampage of this pocket monster knows no bounds, which is why one must constantly fear the emergence of a Gyarados in the Poké world, which destroys everything around it. According to Alpha Sapphire, it may even take a month for this destructive rampage to calm down.
