World of Nightmares

The World of Nightmares is a location exclusive to World of Winx.

Overview
As of now, little to nothing is known of the World of Nightmares, except for how it is a world that exists parallel to the World of Dreams where nightmares reign supreme. Like the World of Dreams, the World of Nightmares can only be accessed through a portal; one that looks much more sinister and green in color when compared to the neatly circular and blue portals to the World of Dreams.

Season 2
In "Tinkerbell is Back," Jim uses Tinkerbell's bell to open a portal to the World of Nightmares. The Spirit of the World of Dreams appears and informs everyone where the gate leads and if the Tree of Life reaches it, all dreams will end forever and only nightmares will remain. The Winx, Matt, and Tinkerbell do their best to catch up to Jim but are unable to move quick enough. Suddenly, as Jim monologues about being King of the World of Nightmares, Smee appears aboard the ship from the hatch and is able to divert it's path. Turning the ship upside down, a treasure chest falls on Jim, tossing him into the World of Nightmares and leaving Tinkerbell's bell behind.

Trivia

 * An inspiration for the World of Dreams and the World of Nightmares might be Marvel Comics' Dimension of Dreams, which is also known as the World of Dreams, and within which exists a dimension called the Nightmare World.