Game:Maleficent

Kingdom Hearts
In Kingdom Hearts, Maleficent has two forms. Her first form is just her standing on a floating platform. She summons Heartless to aid her in battle and uses powerful magic attacks. If you attack her enough, she drops her the platform she is on and is open to attack. You can also cast Gravity on the platform to bring it down. When you defeat her, you get the Cheer Ability for Donald. When you fight her again, she has been turned into her Dragon form by Riku possessed by Ansem with his Keyblade. In this form, she bites at the group, whips her head around, stamps on the floor, and breathes green flames. When you defeat her, you get the Firespark summon gem which contains Mushu.

Kingdom Hearts: Chain of Memories
In Kingdom Hearts: Chain of Memories, you fight her again but only in her Dragon form. She basically has the same attacks as she did in Kingdom Hearts, but with more time in between attacks. When you fight her, the Trick Card creates a pile of bricks which allows you to reach her head (her only weak point) more easily. This also keeps you from being hurt from her stomping attack, however, each stomp destroys some of the bricks.

In Reverse Rebirth, Riku fights Maleficent as well. It is basically the same fight as with Sora, but it is easier since Riku fights her at the very beginning of the game.