Keep shooting him with single shots from your plasma gun when he is exposed. At certain times during the fight, you will not be able to hurt him. Scan him with your visor and it will tell you how to get him exposed to your shots. He will have many different forms in which you have to make him exposed. After many shots to his body, he will open up. Go into Hyper mode and blast away at him, making sure he does not run into you. Keep doing this until he is dead. Then collect your prize and continue on your journey.