Pokémon Colosseum

Pokémon Colosseum, formerly known as Pokémon Stadium 3, is a starter stage in Super Smash Flash 2 coming from the  series. This stage's concept is similarly based on Pokémon Stadium (from Super Smash Bros. Melee) and Pokémon Stadium 2 (from Super Smash Bros. Brawl), in the sense the stage can change into numerous forms based on Pokémon types.

Layout
The main hazard of this stage is its ability to change into numerous forms based on Pokémon types, which happens roughly every minute. Each form consists of a large main platform with an impassable pillar on the bottom, and the layout above this platform depends on the form. There is a large screen in the background that normally displays the current form of the stage and the names of the characters fighting. During a transformation into another form, a flashing image of that form will display instead.

The Normal form of this stage is the main form used at the start that each other form transforms back into. The main platform is green with a Poké Ball symbol in the center, and there are two small soft platforms above the main platform, with one on each side.

The Bug form of this stage takes place in some sort of forest, in which the main platform is covered in grass with a lake in the background. A large log is laid on the main platform and is held up on the right side by a tall group of rocks with a bug-catching net in front of it. A large tree grows in the background on the left side with a slanted platform on a branch in the middle ground. A beehive hangs on the left side of this platform and spider webs appear in multiple places on this form.

The Ghost form of this stage takes place in a haunted cemetery, in which the main platform is covered in dark soil. A gate to the cemetery appears in the background behind a large tree with an evil face. The main feature of this form is a lantern that dangles from the top and lights up areas underneath it, as areas not lit up are pitch black. There are also four soft platforms in the shape of gravestones that float in midair with ghostly purple gas underneath, with two near the middle of the main platform and one on each side near the bottom of it. These platforms become intangible when the area surrounding them is pitch black.

The Steel form of this stage takes place in a construction site, in which the main platform is covered in cement. The middle ground is covered with a group of red steel girders piled onto each other with a red fence behind it. Several large steel pipes appear in the background, including one being lifted and lowered continuously by a crane. Magnemite and Beldum also appear in the background, where they float idly.

Music

 * The main music track is Pokémon Main Theme, a synthetic remix of the title theme from Pokémon Red and Blue.
 * The alternate music track is Trainer Battle, a rock remix of the theme that plays during a battle against a trainer in the Kanto region in Pokémon HeartGold and SoulSilver.

Tournament legality
This stage is a neutral stage, due to its static, highly balanced stage layout when hazards are disabled. Some players even argue that the stage is more balanced than, as there is no top platform for more vertically-inclined players to camp with.

In v0.9b, the stage was banned in online play due to lag-inducing lighting effects. However, the addition of advanced quality settings in Beta has warranted that it be legalized in all circumstances.

Origin
This stage is mainly inspired and modeled after the Pokémon Stadium stages that appear in Super Smash Bros. Melee and Super Smash Bros. Brawl. These stages were in turn based on the Pokémon Stadium games, whose arenas in-game feature a Poké Ball logo in the middle, a crowd watching the battle and, in the case of Gym Leader battles, type-related aesthetics.

The Bug-type transformation may be based off of forest locations in Pokémon games, like Viridian Forest in Pokémon Red, Pokémon Blue, and Pokémon Yellow, Petalburg Woods in Pokémon Ruby, Pokémon Sapphire and Pokémon Emerald, Eterna Forest in Pokémon Diamond, Pokémon Pearl, and Pokémon Platinum, and Pinwheel Forest in Pokémon Black and Pokémon White. In those areas, the player can encounter wild Bug-type Pokémon.

The Ghost-type transformation may be based off of graveyard locations in some Pokémon games, like the Pokémon Tower in Pokémon Red, Pokémon Blue and Pokémon Yellow, Mt. Pyre in Pokémon Ruby, Pokémon Sapphire and Pokémon Emerald, Lost Tower in Pokémon Diamond, Pokémon Pearl and Pokémon Platinum, and Celestial Tower in Pokémon Black and Pokémon White. In those locations, the player can encounter wild Ghost-type Pokémon.

The origins of the stage's name stems from the game Pokémon Colosseum, a spin-off Pokémon title released for the Nintendo GameCube, which could be considered the third game in the Pokémon Stadium series due to the game inheriting the basic stadium style battling seen in those games.

Trivia

 * The background elements of the Ghost form of this stage contain several references to certain Ghost-type Pokémon: the large tree with a face may be a reference to Trevenant, the lantern at the top is shaped similarly to Lampert, the white candles with purple flames are references to Litwick, and there is a statue in the shape of Rotom on each side of the gate.