Same last name ... but NO love between Logan Paul and "Breaking Bad" star Aaron Paul -- with Logan telling TMZ Sports he would beat Aaron's ass if they ever came face-to-face.
Their beef goes back a few months ... when Aaron trashed Logan for his video stunt gone wrong in the suicide forest in Japan. Aaron told Logan to "go rot in hell."
Now, Logan is firing back ... calling Aaron an "Internet bully" -- and warning the actor that if he REALLY wants a piece, he'll end up getting hurt.