The Ice Colossus, misspelled as "Ice Colussus" in the Japanese release, is a replicated form of the Ice Titan. It debuts in Kingdom Hearts Birth by Sleep, appearing alongside Hades in Aqua's story. Ice Colossus can also be fought at Mirage Arena in Kingdom Hearts Birth by Sleep.
 Kingdom Hearts Birth by Sleep
After Hades challenges Aqua to a fight, he reveals his trump card: the Ice Colossus. Hades claims that the rules state that fights do not have to be just one-on-one, and that she can pick someone to assist her as well. Zack volunteers to help but Aqua says she can handle it. She fights Hades and the Ice Colossus two-on-one, and emerges victorious. After the battle, Hades remarks that the fake was not good enough, revealing the Ice Colossus to be an inferior copy of the actual Ice Titan.
The Ice Colossus is a massive being made of ice which is similar in appearance to an emaciated human being. It has fairly long arms that end in clawed, four-fingered hands. Its icy ribcage is always visible, and its upper back is lined by tall spikes. Its head is rather small in comparison to the rest of its body. Its blocky mouth is filled with sharp teeth, its eyes are small and barely visible. It has a spiky crest decorating the back of its head and cheeks. Its upper legs are very thin, while its thicker lower legs are frozen to the ground, forcing the Ice Colossus to constantly break and regenerate them to walk.
The Ice Colossus's name refers to its frozen body, while "colossus" is a descriptive term for anything of gigantic size.
The Ice Colossus is a much easier opponent than the Ice Titan. It mainly assists Hades by bombarding Aqua with ice shards which do minor damage, but cannot be deflected like with the Ice Titan. It can also create shockwaves by punching or stomping the ground, and can breathe a freezing fog of ice.
Simply dodge its attacks and attack the Ice Colossus's legs until it falls over, stunned. A deck that uses -ga level spells, such as Triple Firaga, should be strong enough to take the Colossus down quickly. Then, it is simply a matter of attacking Hades while dodging his fire attacks.
You can also just attack Hades and avoid the Ice Colossus's attacks; once you defeat Hades the match is over.
 A Time To Chill
The Ice Colossus returns as an optional boss in the A Time To Chill round of the Mirage Arena, fought after several waves of Unversed and Zack and Hades have been defeated. The fight will flow similarly to the fight fought in the Olympus Coliseum, albeit the only change is the boss's greatly increased HP and Hades no longer fights with it.