Battle! Samus vs. Predator

Samus has screw attack. Samus cannot be damaged by enemies while screw attacking. With space jump, Samus can screw attack indefinately. If screw attack can't kill Predator (screw attack can't kill Metroids, though it does make her invulnerable to them), she can screw attack untill a shot oportunity presents itself, shoot, then go back to screw attacking.