Norfair is an area located deep in the underground caverns of planet Zebes that has many volcanic based enemies and features, such as a number of superheated rooms that Samus will take damage from if she hasn't yet acquired the Varia Suit, as well as the many pools of magma that Samus can't traverse unless she has the Gravity Suit. The deepest part of Norfair is incredible dangerous, as it is home to the lair where Ridley resides.
In M.U.G.E.N, Norfair has been made four times: once by MDI, twice by BaganSmashBros and once by EXShadow; MDI's version uses sprites taken from the Golden Torizo's boss room in Super Metroid, BaganSmashBros' versions use assets from the Norfair stage as it appears in Super Smash Bros. Brawl, while EXShadow's version uses assets from the Omega form of the Norfair stage as it appears in Super Smash Bros. for Wii U.
This stage does not feature any music
MDI's Norfair stage is almost identical to the Golden Torizo's boss room from Super Metroid, the only difference being the presence of lava beneath the platform that combatants fight on. Like in the source game, the intense heat of Lower Norfair makes it so everything in the background is constantly moving, which can come across as slightly psychedelic, there is also a single blue door on the right side of the stage that would lead to the room containing the Screw Attack. Due to a combination of the stage's floor being higher than usual, a camera that will only start scrolling vertically when a combatant nears the top of the screen and the camera scrolling quickly when it does eventually start moving, characters that have a Super Jump will only just remain visible on screen when they use it, that being said, the stage is just about tall enough to support some form of high altitude battle between flying characters.
The second version of Norfair created by BaganSmashBros still makes use of graphical assets taken from the Norfair stage as it appears in Super Smash Bros. Brawl, though this time the stage is actually referred to as Norfair. Steam from the bottom of the stage quickly rises to the top, while the falling walls of magma that can be seen in the background are in similar places to where they are in the source game, though there is an additional wall of magma appearing in the foreground to the left which can potentially obstruct the view of the fight; every so often, the stage and any combatants on it will start to become enveloped in a reddish glow, and although this effect wears off after a while, predominantly red characters can become very difficult to see while the effect is active. Despite a character still being mostly visible on screen if they were to use a Super Jump, the stage's camera will only start zooming out once they get close to the top of the screen.
EXShadow's version of Norfair uses graphical assets of Norfair's Omega form stage taken from Super Smash Bros. for Wii U, to the point where the only noticeable difference between the stage and its Super Smash Bros. series incarnation being the platform slowly moving up and down to give off the impression that it is hovering; the stage's camera is always zoomed out to a certain distance by default and only zooms out a tiny bit further should the combatants place enough distance between themselves. Several tricks have been employed to try and emulate some of M.U.G.E.N 1.1's features without actually using said features, one of those tricks is the RGB method that's used for the sprites of the stage platform and the magma flowing below it, so as to get around the 256 colour per sprite limitation present in older versions of M.U.G.E.N; another trick is the anti-alias effect on the stage platform, which is actually a single sprite that uses subtractive transparency being layered over the top of the main platform sprites.