The Ocean Dimension is an unknown cut dimension in Crash Twinsanity. It's unknown where it would take place and where its location would be. Concept art made by Danny Flynn shows Crash standing in the ocean. Cortex's lab can also be seen.
Underwater Doc Amok
The only thing that are known about this level is that Cortex would have had a clam on his head, as well as a squid and a shark.
This is where Coco would have been playable. She would go in a submarine and explore the ocean.