To defeat Mogner War Golem (Boss of Bryyo), first dodge and jump over all of his attacks. While doing this, use missiles and your Power Beam to blow up the red orbs on his chest. Try this order: first the stomach, then the shoulders, and finally the back. Shoot them until they are giving off white light. Then, use your Hyperbeam to blow up the now white orb. Do this for all four of them. After you destroy one, the Golem will try to run into you and use his "little jump and create waves of pain" attack. Every time he is about to jump, use Morph Ball Bombs on his feet. They should explode, and you can continue fighting him. Also, when he starts to make red orbs come to his hands, blow them up or you will have to destroy his orbs again.
First, shatter all the red orbs on his body. This is somewhat challenging because he reaches out for more orbs frequently and you must destroy them before he gets them. Try using Charged Shots on the orbs. After you have shattered all the orbs, they will be glow white. Go into hyper mode and shoot the glowing orbs. Only shoot at one orb at a time. You will damage him, but he creates armor on his feet and charges. Also the orbs are covered up. Go into morph ball mode and bomb each of his feet until the armor is destroyed. When the armor is destroyed, the orbs will glow again. Repeat the process until he dies. Note: If you are low on health or Phazon, destroying the green hands and the orbs will replenish them. If done correctly you should have full health most of the time.
