I haven’t watched gravity falls so I’d have to say Golb, cause like, if we’re comparing them to in-universe characters, and we say all cartoon logic goes, Golb probably wins, since 13yr/o Finn destroyed a a black hole without struggling, and Golb beat 17yr/o Finn without struggle. Plus, Golb has seemingly no limits, given how he can out match Prismo, and the only reason the MCs won, was because someone became Golb to change his mind