Another Dimension

Another Dimension is the name given to the interdimensional space or tunnel between Halcandra and Planet Popstar in the Kirby series. It serves as the final level of Kirby's Return to Dream Land and is where Magolor is defeated. It is also the home of the Doomers, Sphere Doomers, the Grand Doomer and the Greater Doomer. It is generally accessed via blue star shaped dimensional rift.

Kirby's Return to Dreamland
Throughout the game, various dimensional rifts will open, which leads Kirby, Meta Knight, King Dedede and Bandana Waddle Dee to fight Sphere Doomers for the Energy Spheres they have stolen. It is later opened by Magolor using the Lor Starcutter's Halcandran technology in order to start off his scheme of universal conquest once he had stolen the Master Crown. Magolor is however defeated inside Another Dimension thanks to Landia's help and the Master Crown is destroyed. Without the Master Crown to create a stable passage between Halcandra and Pop Star, the whole dimension collapse as the four heros returns to Pop Star.

Kirby: Triple Deluxe
Another Dimension is the seventh and last stage of the Kirby Fighters mini game and is the only stage to not reappear in Kirby Fighters Deluxe, instead being replaced by the Fountain of Dreams.

Kirby: Planet Robobot
It is implied that Susie was sent to Another Dimension as a result of one of Star Dream's experiment, which led her father to believe that she died and kickstarted the whole series of events that led to Kirby: Planet Robobot. It is also where Susie got the data on the Sphere Doomers that allowed the Holo Defense API to recreate them.

At the end of Meta Knightmare Returns, Star Dream summoned Galacta Knight from a portal similar to those that leads to Another Dimension. It is also possible to see the Lor Starcutter flying through what looks like Another Dimension when Galacta Knight tears the fabric of reality appart in one of his attacks.

Team Kirby Clash Deluxe
In Team Kirby Clash Deluxe, Greater Doomers emerges from a portal leading to Another Dimension just before his fight. Parallel Susie, which is a Mirror World version of Susie, also comes out of a similar portal and is taken back into one after her defeat, which is supposed to mirror what happened to her regular world counterpart.