Ganon

Ganon is Ganondorf's second form, a large blue warthog. Ganondorf changes into Ganon through the use of the Triforce of Power, and also he remains in this form in the Dark World. Ganondorf appears as Ganon in all the Zeldas up to and including The Legend of Zelda: Ocarina of Time, the form also occurs in the Oracle of Seasons and Oracle of Ages' linked ending, The Legend of Zelda: Four Swords Adventures, and is the second phase of the final battle in The Legend of Zelda: Twilight Princess.

Appearances
After Ganondorf broke into the Sacred Realm and captured the Triforce, his evil made it become the Dark World, where a person's form changed to fit their inner self. This revealed Ganondorf's true self, Ganon.

The Legend of Zelda
Ganon broke free of the Dark World and attacked Hyrule in an attempt into steal the Triforce of Wisdom. He made his base of operations in Death Mountain under Spectacle Rock. Zelda split the Triforce into eight shards, and Link assembled them to fight Ganon, and killed him with the Silver Arrow.

Years later, in Zelda II: The Adventure of Link, Ganon's army made an attempt to revive him by spilling Link's blood onto Ganon's ashes, but failed.

The Legend of Zelda: A Link to the Past
Ganon sent a portion of his spirit, which was manifested into Agahnim, into Hyrule to break the seal by sending the Maidens, descendants of The Seven Sages, into the Dark World. Link traveled into the Dark World, where he destroyed Agahnim. After the battle with Agahnim, he battled Ganon in the Pyramid of Power, where he was bested by a Silver Arrow. The seal on the Dark World was strengthened.

The Legend of Zelda: Ocarina of Time
For the first time, Ganondorf would transform into Ganon, in which a long battle ensued between him and Link. In the end, Zelda held him down and allowed Link to impale his head, and while he was in a pained rage, the Seven Sages opened the void to the Sacred Realm, sealing him there.

The Legend of Zelda: Oracle of Ages and The Legend of Zelda: Oracle of Seasons
In the linked ending of the Oracle subseries of Zelda games, it is revealed that the events of the two games were started by Twinrova in an attempt to resurrect Ganon. In the end, they succeeded, though the ritual was incomplete, and Ganon became a mindless beast.

Ganon was powerful due to the fact that he attacked randomly due to no ability to think, though he was sealed away by Link once again.

The Legend of Zelda: The Wind Waker
In the timeline created when Ganon was sent into the Sacred Realm, he somehow escaped imprisonment, and in Ganon form, began to take over Hyrule. Link did not appear. In response, The Gods flooded Hyrule to seal away Ganon and his army.

Over the years, Ganon managed to escape, though he was cut off of his power, therefore he was unable to keep himself in Ganon form and changed into Ganondorf. He eventually was killed by Link.

The Legend of Zelda: Twilight Princess
Ganondorf was captured and put up for execution by the sages of the Arbiter's Grounds. He survived execution by absorbing the evil and malice of the imprisoned Twili. He crushed a sage, and hastily the others activated the Mirror of Twilight and flung him into the Twilight Realm, where he used Zant to access Hyrule again, though in spirit form.

Taking over Hyrule Castle, Ganondorf was given a physical body after Zant's magic was delivered to him after his assassination by Midna and a new Link. During the final battle, Ganondorf possessed Zelda by turning into Twilight, and after being purged from her body, reassembled himself into Ganon.

Ganon charged after Link through Twilight portals, appearing randomly and sudden. Link was able to fire arrows into Ganon's head, leaving his stomach susceptible to attack. Eventually, Link morphed into his wolf form and, with the help of Midna, threw him to the side, and attacked his stomach.

Eventually, Ganon's body began to degenerate. Ganon's spirit emerged from the body, and battled Midna equipped with the Fused Shadows. In the end, Ganon emerged victorious, and his spirit was manifested into Ganondorf's body, though he would wind up being defeated.

Four Swords Adventures
Ganondorf stole the Trident and then the Dark Mirror, which he used to summon Dark Link, who he sent to trick Link into releasing Vaati from the Four Sword. While Vaati distracted the Links and imprisoned the Shrine Maidens, Ganon absorbed the power of the Maidens. At the end of the game, Ganon appears as the final boss as a twist ending, fought in the Dark World underneath the Tower of Winds, where he is defeated after Link fires a light arrow into Zelda's energy bomb, which pierces him. He is then sealed away in the Four Sword.