Mushroom Kingdom (SSB)
Mushroom Kingdom (いにしえの王国, Ancient Kingdom) is the only unlockable VS. Mode stage in Super Smash Bros., and is not available in any other Smash game, although there's the graphically similar stage Mushroom Kingdom in Super Smash Bros. Melee. This stage is unlocked by clearing 1P Game with the eight original characters and by playing on every already playable stages in VS. Mode. This stage is the only one which is never seen in 1-Player mode. Even if this stage is unlocked, Mario and Luigi will still be fought on Peach's Castle.
In competitive play
This stage is universally banned in standard tournaments due to hazards such as the POW blocks and randomized Piranha Plants disrupting gameplay, the pipes allowing heavy side camping, and the walk-off blast lines allowing even further side camping and allowing characters who can chaingrab past the blast line (such as Pikachu using its forward throw) to KO at very low percentages. It is the only stage along with Sector Z that has never been considered to be legal, though is a common friendly stage due to its randomness.
In the middle of this stage is a pit. To the right of it, there are two soft floating platforms, and a pipe to the right of them. To the left of the hole, there is a single floating soft platform, and a solid brick platform left of that which extends to the edge of the stage.
This stage is from Super Mario Bros. In Super Mario Bros. the player can go down pipes to an underground level or bonus level; when underground, the player has to go into pipe to return to the overground. In this stage, these green pipes are retained and can be used to warp to two other parts of the stage. Super Mario Bros. also feature these scale-like platforms that go down on the platform the player is standing on while the other platform goes up. These platforms are in this stage and work as they did in Super Mario Bros.
In the arcade game Mario Bros., the goal is to hit the enemies from under a platform to flip them over and get to the top of the platform to kick them off. If the player feels overwhelmed by how many enemies are on the screen at once, the player can go to a POW block to knock all the enemies on their back. In this stage a POW block appears. If a player is to hit the POW block it sends his or her opponents upward.
There are many elements in the background from Super Mario Bros. such as Hammer Bros., giant mushroom platforms, vines, a flag pole, etc.
The music is the original overworld theme in Super Mario Bros., it would be reused for Melee's Mushroom Kingdom.