I’ve thought about this myself! I can’t imagine trying to write Oscar as a human at any point, but it’s too fun to think about what superpower it would give him anyway.
I ended up with pyrokinetics! Oscar would be able to create little flames and control them to a degree. Can you imagine him discovering that? One second he’s got a tiny fireball in his hand and he doesn’t know what to do with it. Looking around at Sam and Dean like halp!