Koopalmier
Goomba
Super Mario Bros.: The Lost Levels is called a "parallel world" to Super Mario Bros. in the Famicom Disk System manual.
Super Mario Galaxy 2 is also called a "parallel world" to Super Mario Galaxy in Japanese as far as I can find.
Regarding Super Mario Galaxy, Rosalina also tells you that you can travel to a "new world" if you collect all 120 Power Stars, which turns out to be the Super Luigi Galaxy bizarro world in which Luigi meets Luigi even though Mario also exists.
There being an alternative universe is not only relevant to the Mario series, but also important since it was re-used in Galaxy 2. It brings up many issues - how do we know if a game takes place in universe A or universe B? What does this imply for 3D Land's Special Worlds, which seem to also be alternative and more difficult versions of the regular levels, but can be traveled to at will with a Warp Pipe (it's actually where Dry Bowser holds Luigi)? What about Worlds Mushroom, Flower and Star in NSMB2? What about when places from both SMG1 and SMG2 appear in the same game, such as Fortune Street? Do we play as the same Mario traveling between alternate realities on occasions, if 3D Land implies that traveling from one universe to another is possible? Does New Super Luigi U take place in the alternate universe? What do alternate universes imply for the RPGs, particularly since we already know about one (the Paper Mario world)?
Things don't get more simple if we take into account different versions of the same game that have particularly different contents (the Super Mario Advance remakes, Game Boy Donkey Kong, Mario 64 DS...).
Super Mario Galaxy 2 is also called a "parallel world" to Super Mario Galaxy in Japanese as far as I can find.
Regarding Super Mario Galaxy, Rosalina also tells you that you can travel to a "new world" if you collect all 120 Power Stars, which turns out to be the Super Luigi Galaxy bizarro world in which Luigi meets Luigi even though Mario also exists.
There being an alternative universe is not only relevant to the Mario series, but also important since it was re-used in Galaxy 2. It brings up many issues - how do we know if a game takes place in universe A or universe B? What does this imply for 3D Land's Special Worlds, which seem to also be alternative and more difficult versions of the regular levels, but can be traveled to at will with a Warp Pipe (it's actually where Dry Bowser holds Luigi)? What about Worlds Mushroom, Flower and Star in NSMB2? What about when places from both SMG1 and SMG2 appear in the same game, such as Fortune Street? Do we play as the same Mario traveling between alternate realities on occasions, if 3D Land implies that traveling from one universe to another is possible? Does New Super Luigi U take place in the alternate universe? What do alternate universes imply for the RPGs, particularly since we already know about one (the Paper Mario world)?
Things don't get more simple if we take into account different versions of the same game that have particularly different contents (the Super Mario Advance remakes, Game Boy Donkey Kong, Mario 64 DS...).