Marshmallow/The Neo Ice Colossus
Marshmallow, or rather the New Ice Colossus, is a newly created Titan formed from the doubt and fear in Queen Elsa's heart. It serves as her rather more determined personal bodyguard and security of the Ice Palace, and is fought as a boss in "Return of the Keyblade".
Hades later takes control of the creature, and has it sent amongst a horde of other giant monsters to wreak havoc in the Keyblade Graveyard.