Phantom Ganon is a recurring boss in The Legend of Zelda series.
Ocarina of Time
Phantom Ganon here guards the Forest Temple. In the room where you fight him, there are many paintings of the same river on the wall; Phantom Ganon will jump into one of them with his horse. Quickly pull out your newly aquired fairy bow and check the paintings; it will appear he is galloping towards you in two of them. The painting with the purple ripple is the one he will jump out of. When he's coming out(when he turns white), shoot at him with your bow; he will return and the whole routine starts again, until he takes sufficient damage to be knocked off his horse. However, if you pick the wrong painting, get out of your aiming mode and rush to the edge of the room: (or just stay where he can't hit you for the first phase) Phantom Ganon will throw down a ball of electricity which shouldn't hurt you if you're on the edge.
When he's off his horse, he will shoot a ball of electricity at you again. Hit it back with the Master Sword or a Bottle. He might hit it back several times, but when he goes down rush at him and attack with all your might (jump attacks or rapid Spin Attacks will do fine). Then he'll start flying again... you know what to do. If you've depleted about half of his health, it will sometimes do another attack: He will twirl his staff a few times, letting off small magic sparks to show he's about to attack. Then he will charge at you, doing three hearts of damage. If you defeat him, you will gain a Heart Container and the Forest Medallion.
The Wind Waker
You have encountered Phantom Ganon before in the Forsaken Fortress, but now he is stronger and more agile than before. If he emits a singular blue orb at you, bounce it back and forth with your Master Sword until it collides with him and causes him to fall. At this time, run up and give him a final blow to destroy him. When he sends a giant red orb that splits up, do a spin attack to send it back to him. But beware, if he makes shadow appearances of himself slash them all quickly to reveal the true Phantom. The last time you encounter this foe, you must use your Light Arrows to finish him once and for all.
Four Swords Adventures
One of Ganon's most feared minions is back, and he is as strong as ever, though he hasn't got any new tricks up his sleeve this time. The only "secret" to beating him is to patiently wait for him to fire his energy-balls at you, and then play a little ball with him, knocking it back and forward between you, with you using your sword. Once he is stunned, run up to him and slash away all you can before he gets his act together again. Repeat until he's down.