Pokémon Stadium 2
Overall, this stage works very similarly to Super Smash Bros. Melee's Pokémon Stadium: it switches from a basic version to type-inspired transformations. The layout of the basic version is extremely similar to the Melee version, with a main platform with a solid pillar underneath and two floating soft platforms on the sides. The background features a crowd, much farther away than the one in the original Pokémon Stadium, and a screen which, like the one in Pokémon Stadium, displays either the battle, a symbol denoting the upcoming transformation, or the current standings of each player and the time remaining.
The other transformations, however, are all completely new. Like in Pokémon Stadium, they appear in no specific order and it is even possible for the stadium to change into the same type twice in a row. However, the stage always begins on the standard arena and has to revert back to its normal state before transforming again. Several Pokémon appear in the background during the various phases, with no actual effect on the battle.
The Electric version features two slightly raised conveyor belts which occupy the sides of the main platform, both pushing outwards. The center of the main platform is static. There are three soft platforms in varying locations: two, one above the other, are over the middle of the stage, while the third can be over either conveyor belt.
The Flying version features fans in the ground which create an updraft, severely lowering the gravity: all characters' jumping abilities are enhanced and their falling time is increased. Characters flung upward have a much higher chance of being Star KO'ed. The updraft only extends above the platform. No other platforms are present, giving the stage a Final Destination style layout. The floor is also slightly raised.
In the Ground variation the layout changes to a large solid mound of dirt on the left and a hut built into a tall rock on the right. The hut provides two platforms, the lower one being longer and curved, and the higher one being short and flat. No physics alterations are added.
In the Ice version all platforms and surfaces extremely slippery, so characters are more likely to trip. A hut can be seen in the background, and there are two icy platforms that slope inwards slightly.
The Omega form only features the basic version of the stage, with the floating platforms removed but the pillar at the bottom still present. The jumbotron doesn't display any stats and only shows the battle in progress without zooming into any of the characters except in 8-Player Smash.
Pokémon Stadium 2 is a very controversial stage; it is usually banned in tournaments, although it is allowed as a counterpick in more liberal rulesets. This is because the majority of its transformations are widely considered disruptive to normal gameplay: the electric transformation produces fast conveyor belts that force players to camp the ledge or fight in the middle of the stage; the wind transformation significantly reduces gravity, which slows aerial approaches and results in earlier vertical KOs; and the ice transformation creates slippery terrain which universally decreases traction and slightly increases tripping chance, making more precise movements difficult. Additionally, like the original Pokémon Stadium, all its transformations except for ice are susceptible to camping.
Some smashers, however, debate this stage's legality, arguing that its perceived disruptive elements are either due to player error or actually beneficial to gameplay. For example, they claim that players can camp out the electric transformation, and that any self-destructs are due to unfamiliarity with the stage rather than a flaw in the stage itself. They also argue that the wind transformation, while actually disruptive, does not last long enough to significantly impact the match. Finally, they suggest that the ice transformation actually enriches gameplay because its terrain boosts the speed and slide distance of DACUSes and slide smashes, and causes shields to be pushed back more, forcing the game to be played more offensively.
Based on these arguments, a few vocal smashers even claim that Pokémon Stadium 2 is actually the most neutral stage in the game. Regardless, it remains banned due to the very specific ways in which players have to adjust to the disruptive nature of transformations.
Like its predecessor, this stage seems to be based on the arenas from the Pokémon Stadium series. Its name could be a be a reference to the game Pokémon Stadium 2 (either Japanese or international) for the Nintendo 64.
The flying transformation's aesthetics are reminiscent of Valley Windworks from the Sinnoh region: they both feature wind turbines and, in Diamond/Pearl/Platinum, the Valley Windworks was the only location where a Drifloon, like the one appearing on this stage, could be encountered.
The electric transformation's mechanical appearance could be a reference to the recurring Power Plant setting in the series, where Magnemite, Magneton and Electabuzz (the previous forms of Magnezone and Electivire) can be often encountered.