Warp Door

Warp Doors (or simply doors) are objects appearing in several Mario games that take the player to another part of the level. Most of them are unlocked, while some, known as Key Doors, require a key to be opened.

Super Mario Bros.: The Lost Levels
In Super Mario Bros.: The Lost Levels (and to a much lesser extent, All Night Nippon Super Mario Bros.), Warp Doors only appear in World 8-4 and World D-4, after Bowser (Fake Bowser in the Family Computer Disk System version of World D-4) is defeated. Both lead to Princess Peach. Despite VS. Super Mario Bros. having the same ending as The Lost Levels and All Night Nippon, there is no door leading to Peach after Bowser is defeated, much like in the first game. The door does not appear in any of the SNES remakes, instead being replaced with Peach locked inside a cage suspended over a pit of lava.

Super Mario Bros. 2
In Super Mario Bros. 2, Warp Doors are the main means of transporting between areas. The game consists of three different types of Warp Doors: red swing-open ones, doorless entryways, and special doors with keyholes that require the player to search for the Key in Phantos' lairs to open those doors. They also serve as checkpoints as, on dying, the player would resume from the last door they passed through.

In Super Mario All-Stars and Super Mario Advance, a pair of dark yellow double doors (similar to Super Mario World's) replaced doorless entryways while in the overworld areas, and a giant iron bar door with a Bob-omb emblem appears as the cave entrance in World 6-3.

Super Mario Bros. 3 / Super Mario Advance 4: Super Mario Bros. 3
Doorless entryways are also used in the Nintendo Entertainment System version of Super Mario Bros. 3. In Super Mario All-Stars and Super Mario Advance 4: Super Mario Bros. 3, they are replaced with wooden doors. Big Warp Doors also appear in both of Bowser's boss arenas, which open after he is defeated, and both lead to Princess Toadstool. Another variant known as Magic Doors appear in World 4-6; when entered, Mario can transition between giant and normal-sized versions of the stage.

Super Mario World / Super Mario World: Super Mario Advance 2
Warp Doors made from wood are used mainly in Ghost Houses, Fortresses, and Castles in Super Mario World and its remake, to transport Mario or Luigi to another room. Big ones debut in this game, serving as boss rooms' entry points.

New Super Mario Bros. series
In the New Super Mario Bros. series, Warp Doors have appeared in many Ghost Houses, Castles and Towers, as well as at the end of each Castle and Tower throughout the series leading to the boss. The regular Warp Doors now has the control pad and an up arrow on them. Some doors in Ghost Houses are fake; if the player tries to open one, it disappears and four Boos run away, leaving a coin behind.

Super Mario 3D series
Warp Doors also appear in Super Mario 3D Land, Super Mario 3D World and Super Mario 3D World + Bowser's Fury, in Toad Houses and in some stages.

Super Mario Maker series
In Super Mario Maker and Super Mario Maker for Nintendo 3DS, Warp Doors can be used as course elements. They transport the player to a different part of the area. Up to 8 doors (4 pairs of doors per area) can be placed in the level. As of the 1.20 update, players can knock multiple times on doors in the Course Maker to reveal Weird Mario. The 1.30 update introduces a variation: The P Warp Door, which cannot be activated until pressing a P Switch. Another variation introduced on the 1.40 update is the Key Door; they can only be opened with a key, another feature introduced in this update.

Warp Doors reappear as course elements in Super Mario Maker 2 under the Gizmos section and can be used in all game styles, including the Super Mario 3D World style. Like the previous game, players can knock multiple times on doors in the Course Maker to reveal Weird Mario.

Super Mario Run
Warp Doors reappear in some levels in Super Mario Run, using their ghost house appearance from New Super Mario Bros. U. They mainly appear in ghost house levels, where they help the player advance from one room to another, but one such door also appears in Cutting Edge Spire where it leads the player to the end of the level. In the level Ghost Door Deception, there are multiple fake doors and a real door in each room. The player can tell which door is fake by the fact that it shakes periodically. In Boohind Lock and Key, there is one Key Door in every room.

Super Mario Odyssey
Warp Doors appear again in Super Mario Odyssey. One type of Warp Door is colored red with a golden top hat in the middle of it that can only be opened by throwing Cappy at it. Another type is one that is colored blue that can only be opened by throwing Cappy onto a Scarecrow, thereby forcing Mario to traverse whatever is behind the Warp Door without the aid of Cappy. The third type of Warp Doors are pink-colored ones with locks on them that can only be opened by wearing a specific outfit and talking to the nearby NPC, who will allow Mario access to whatever is inside. The final type of Warp Doors are pink doors without locks, and they can lead Mario to different areas, such as a shop, the Slots minigame, or another area in the same kingdom.