The Rock Titan is an enemy from Kingdom Hearts and Kingdom Hearts Re:coded. The Rock Titan makes a cameo appearance in Kingdom Hearts II during the opening cinematic for the Olympus Coliseum. However, he isn't credited in Jiminy's Journal. It originally appeared in the animated film Hercules, under the name Lythos. He is the final fight in the Hades Cup in Kingdom Hearts, and inhabits Layer 15 of Olympus Coliseum as one of the four sources of bugs in Kingdom Hearts Re:coded.
 Kingdom Hearts
Following Sora's completion of the Hercules Cup, the Rock Titan appears as the final contender in the Hades Cup. Sora, Donald, and Goofy enters the Hades Match alone and finds the colossal, awaiting them, inside the dim, darkened Coliseum. The group takes the Rock Titan on in battle and proves to be victorious, strengthening their power of teamwork.
 Kingdom Hearts II
 Kingdom Hearts Re:coded
The Rock Titan is the one of the four sources of the bugs in Olympus Coliseum, and resides within the Keyhole, on Layer 15. Together, Data-Sora, Hercules, and Cloud are able to defeat him and keep advancing through the world.
 Other appearances
 Kingdom Hearts III
In the D23 Expo Japan 2013 trailer for Kingdom Hearts III, Sora, Donald, and Goofy are on a "Big Magic Mountain" train ride going around the Rock Titan in a mountain. Sora attacks the Titan a couple of times before jumping on top of the Titan's hand and landing back onto his seat. Sora leads the train upwards into the sky, high above the Titan, turns around facing the Titan and sends the train ride right into the Titan.
The Rock Titan is a gigantic, bulky creature that seems to be composed entirely of rough, uneven stone. His body is very large and barrel-shaped. His legs are short and its feet are flat, while his arms are relatively long and end in four-fingered hands. He has two comparatively small, draconian heads placed side-by-side on the top of his body. Both heads have thick necks, a peculiar lower jaw with four very large, blunt teeth. His eyes are very small and red, and the inside of both mouths are red as well.
The Rock Titan's name references his stony body, while "titan" is derived from the Titans of Greek mythology, which were loosely represented by the Rock Titan and his companions in Hercules.
Lock on to one of the Rock Titan's big feet and attack him with combos (such as Ars Arcanum and Graviga). When the Rock Titan falls on his back, use the Superglide ability to float to one of the heads and attack from the far side. Be careful though, as the heads will swing at you; Dodge Roll/jump to avoid damage. Beware of the shock waves it releases, a single foot-stomp can deplete more than half of Sora's HP. The suggested magic spells to use in this battle are: Curaga and Aeroga.
However, a somewhat faster plan is to equip a powerful Keyblade (such as Lionheart, Oblivion, or Ultima Weapon), and repeatedly hammer the legs with Arcanum or Sonic Blade until he falls down. Then, just keep using Arcanum on the heads, as it will deal a large amount of damage. Using this method, the only magic you really need is Curaga. However, if you use Aero, he will take damage simply by you being near him.
Note that each hit taken by the Rock Titan gives you 1 Tech Point, thus you have an option of returning to the battle with the Rock Titan to level up quickly.
The Rock Titan has few attacks, they are also not used very often. The first one consists of a ground attack in which he lifts his hands and pounds the ground releasing a large shockwave that can be easily evaded by jumping. The second attack, similar to the first, consists in the Titan lifting one of his feet and stomping it down. The last (and most powerful) attack appears when he's knocked on the ground and Sora gets the chance to attack his heads; with biting similar to Cerberus' the Titan tries to keep Sora's attacks at bay.
The Rock Titan first appeared in Hercules as part of Hades' evil plot. When the planets align, it is the opportune time to summon the titans, supposedly. With Hercules' power, Hades destroys the prison in the ocean where the Rock Titan and company was and the titan climbs out of the ocean wreaking havoc on Greece. The titans head for Mount Olympus, where they attempt to get rid of Zeus. Hercules later comes to the rescue by using the Wind Titan to suck the titans up and send them flying into space putting an end to the Rock Titan.
 See also