He follows you around because you released him from the Pokeball. Otherwise, he'd stay there and let you carry him.

[Strangers usually don't call him "Rob." They usually call him "Robin," "the Boy Wonder," or "Robin, the Boy Wonder." Dude was seriously informal or seriously confused.]

Look, it takes some time to get combobulated after landing here. I don't know how you define "new," the costume really only changes when I get taller.