Shia LaBeouf was repeatedly PUNCHED IN THE HEAD by a shirtless, hairy-bellied man on a Vancouver sidewalk last week -- and TMZ has obtained footage of the brutal ass whooping.
It's unclear exactly what provoked the attack -- but we're told Shia originally got into it with the man inside a bar called Cinema Public House ... and after security kicked them both out, the man tore off his shirt and unleashed the fury all over Shia's face.