Phanto

Phantos are large, seemingly-living masks that appear in Yume Kōjō: Doki Doki Panic and Super Mario Bros. 2, where they are found guarding keys; according to the game's manual, they often guard various other treasures as well. Their name is a shortened form of the word "phantom", another word for ghost or specter.

In Yume Kōjō: Doki Doki Panic, the Phanto's expression and color scheme most resembles its original artwork; starting with the original NES version of Super Mario Bros. 2, they are given a distinctive evil grin, and subsequent remakes portray them as golden in color instead. Most of its appearances outside these games either draw from its original appearance, or else use the gold sprite from the remakes.

Super Mario Bros. 2
Phantos appear as semi-common enemies in Super Mario Bros. 2 and its subsequent remakes and ports, and are seen guarding keys in caves or in jars. Phantos simply remain immobile and harmless unless the key they are guarding is taken, at which point one of the Phantos will animate and ceaselessly chase whoever stole it; some of the remakes make this Phanto slightly different in appearance from the others. Phantos can follow the player through other screens and rooms, even including Subspace. They cannot be permanently defeated&mdash;if the player drops the key while a Phanto is chasing them, it flies away and leave them alone until the key is picked up again, and will only give up the chase for good once the key is used to unlock its door. A Phanto can be temporarily defeated only with the combination of a Stop Watch and a Super Star; the Super Star alone does not affect it, and even after destroying the Phanto, a new one will replace it as soon as the player enters another room while carrying the key.

A number of immobile and harmless Phantos can be seen in Wart's room in all versions of the game. In the SNES and GBA versions of Super Mario Bros. 2, larger Phantos can be seen in the background of certain jar interiors; the eyes of these larger Phantos will glow red repeatedly once the key is grabbed. In Super Mario Advance, if the player drops the key or loses a life, the Phanto appears enlarged as it flies away, creating the illusion of it flying towards the camera.

The Super Mario Bros. Super Show!
Phantos make two appearances on The Super Mario Bros. Super Show!, with the first one making its debut in "The Ten Koopmandments". After Koop Tut had trapped Mario, Luigi, Princess Toadstool and Toad inside a pyramid, the four heroes encounter the Phanto, which proceeded to chase them until they managed to escape from the pyramid. Another Phanto made a brief cameo appearance in "Escape from Koopatraz" as a member of Judge Koopa's jury.

BS Super Mario USA
In BS Super Mario USA, big Phantos twice the normal size sometimes appear and chase the player even without keys involved.

Mario Kart series
Sprites of Phantos, taken from Super Mario Bros. 2, are sewed on the carpets decorating the racecourse of Shy Guy Bazaar in Mario Kart 7 and Mario Kart Tour.

Trivia

 * In Chapter 6-3 of Super Paper Mario, the Sammer Guy of the 63rd gate is named "Phanto Grin".
 * In Kirby Super Star Ultra, the Phanto Mask appears as a treasure in The Great Cave Offensive in place of the Zebra Mask from the original Kirby Super Star.
 * An enemy called Two Face appears in Kirby's Dream Land and Kirby Star Allies, behaving in a similar way, although it can be destroyed.