Tenth Dimension

From Bandipedia, the Crash Bandicoot wiki

Tenth Dimension
Inhabitants	Evil Twins, Evil Crash, Ants
First Appearance	Crash Twinsanity

The Tenth Dimension is the moral opposite of Crash's home dimension. Everything that is considered benevolent in Crash's dimension is manevolent in the Tenth Dimension and vice-versa. Where Crash's dimension is bright and colorful, the Tenth Dimension is dark and gloomy. 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.