Tenth Dimension

The Tenth Dimension is the moral opposite of Crash's home dimension. Everything that is considered benevolent in Crash's dimension is malevolent in the Tenth Dimension and vice-versa. Where Crash's dimension is bright and colorful, the Tenth Dimension is dark and gloomy as seen when iceberg lab telephort into 10th dimension the iceburg is replaced by a volcano. The Tenth Dimensional equivalent of N. Sanity Island is the barren Twinsanity Island, where the feral and ferocious Evil Crash resides.

As a child, Doctor Neo Cortex accidentally sent his pet parrots Victor and Moritz to the Tenth Dimension while testing his prototypical Evolvo-Ray. It is claimed that the severe "reverso-radiation" in the Tenth Dimension sharpened the skills of the parrots and warped their "fragile, egg-shelled minds", causing them to become the Evil Twins. In an earlier version of the game, this reverso-radiation would affect Crash and Cortex upon entering the Tenth Dimension, causing their personalities to switch. This would lead to a reversal of the Doc Amok levels seen earlier in the game (named "Mock A Doc"), in which Crash, who has taken on the form of Evil Crash, must attack the now-benign Cortex and make him as angry as possible.

Trivia:

Cortex once said "We were supposed to visit two, but we ran out of time" just before going to the Tenth Dimension.