When using the Classic Tone keyblade's Shotlock, Sora actually turns into the same exact cartoony monochrome form that he had donned when he was in the retro Timeless River world in Kingdom Hearts II. In addition, the 'portals' he comes out of and goes into during the Shotlock are extremely similar to the doorways that lead to different areas of the world that are used by the characters in Timeless River's story.
Contributed by PirateGoofy