Why did this legendary create Dynamax? Some people think it's just a random 'mon that has Dynamaxed, clearly ignoring the fact that the portal is originating from its mouth.

So why would it? What benefit would it have of turning other Pokémon giant and enraged? Just to destroy?

Is it a dark god Pokémon with an evil agenda, trying to bring about Ragnarok by covering the world in giant titans?