Plessie

Plessie is a friendly character resembling a (yet referred to as a "dinosaur" by Nintendo) that debuted in Super Mario 3D World. In the game, it allows the playable characters to ride it through certain levels, similarly to Dorrie in Super Mario 64 / Super Mario 64 DS and New Super Mario Bros. Plessie's name is a portmanteau of "Plesiosauria" and "Nessie." The former is an extinct group of large marine reptiles that are often confused as dinosaurs, whereas the latter is the nickname given to the. Its design shares some features with the design of Yoshis, such as the bipedal posture with short legs, the white soft tissue that spans the lower part of the body, big oval eyes pointing forward which feature a white sclera, the nostrils being hosted near the top of a round protruding end of the upper part of the muzzle, and a crest on the back of the head, although the shape of the latter is different. They also share the same suffix, -sshi (「ッシー」), in their Japanese names.

Super Mario 3D World / Super Mario 3D World + Bowser's Fury
In Super Mario 3D World and its Nintendo Switch port, Plessie first appears in World 1-4, Plessie's Plunging Falls, where Mario and company must ride it through a river to reach the Goal Pole. It also appears in World 5-1, Sunshine Seaside;, Plessie's Dune Downhill, where it slides through sand; , Deepwater Dungeon; and , Rainbow Run. Plessie also makes a few cameos outside of these levels. In, Champion's Road, it appears at the end of the stage alongside other friendly non-playable characters gather to congratulate the player. It also appears in the game's title screen, and in the credits scene.

To control Plessie, players can tilt either the control stick or control pad, depending on the controller. To speed up and slow down, players tilt up and down respectively. Players can also press the jump button to jump, which can be used to defeat enemies and reach higher ground. If more players are riding Plessie, they can cooperate to tilt it further. If Plessie falls off a course, however, the lives lost is dependent on the amount of players riding it.

Plessie also appears in Bowser's Fury, where it helps Mario traverse the waters of Lake Lapcat by carrying him on its back. Like in Super Mario 3D World, Plessie is able to swim and slide on ground. However, the player now has full control over Plessie's movements, and can also use a new move to dive underwater. While underwater, Mario can dodge enemies and Fury Bowser's attacks. If the player presses the jump button as soon as Plessie exits the water, it will launch forward with a sparkling effect, enabling for faster travel.

At the end of the campaign, by collecting the three Giga Bells, Plessie becomes to defeat Super Bowser, and permanently stays as  even after returning to normal size.

Super Smash Bros. Ultimate
Plessie appears in Super Smash Bros. Ultimate as a support spirit. It gives fighters the ability to remain in the water indefinitely. The fight to capture the spirit takes place on Great Bay, against a giant Yoshi simulating Plessie.

Physical appearance
Plessie is modeled on extinct aquatic reptiles. Plessie is three to four times as tall as Mario, although the artwork made for the Super Mario 3D World Original Soundtrack shows it being around only twice as tall as Mario. Plessie is visibly fat, and this trait is actually used to slide on its belly outside bodies of water. The bottom of each foot, including the toes, is fully covered by a white pad. The back features four darker stripes with rounded borders that are perpendicular with respect to the tail. Plessie's head features two big eyes, each with an orange eyelid, a white sclera, and a big oval pupil surrounded by an aqua green iris. The upper part of the muzzle is elongated like that of a, with a white protruding end hosting two nostrils near its top. The tail is long and ends with a three-lobed structure resting on the coronal plane, similar to the crest and having the same cyan color as well. Plessie is always seen wearing a red bandana knotted on the left side of the neck.

Theme music
In both Super Mario 3D World and Bowser's Fury, Plessie is given its own theme. In the former, Plessie's theme plays before hopping on Plessie and upon dismounting it in stages such as Plessie's Plunging Falls. The theme is mainly ambience music featuring bongos. In the latter, Plessie's theme plays when riding Plessie. The theme is an upbeat version of Lake Lapcat's theme featuring additional instruments such as violins and trumpets.

Trivia

 * Before and after riding Plessie, the GamePad player can pet it by rubbing it with the stylus. Doing so makes it laugh and give them five Coins.
 * The music that plays while riding Plessie in the levels he appears in is an arrangement of "Slider" from Super Mario 64.
 * The official European sites of Super Mario 3D World feature a short description of Plessie in which it is stated to be a dinosaur, referring to it as a male in languages where the term dinosaur is typically male. However, in the German translation of the Encyclopedia Super Mario Bros., where Plessie's species is not stated, it is referred to as being female.