Plessie is a friendly character resembling a nothosaur (yet referred to as a "dinosaur" by Nintendo). Plessie's name is a portmanteau of "plesiosaur" and "Nessie." Plessie has her own levels, and appears in the middle of some. 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 Loch Ness Monster. Her 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. Plessie's Plunging Falls is the first time she appears. Other appearances include Sunshine Seaside, Plessie's Dune Downhill, Deepwater Dungeon, and Rainbow Run. She also appears to congratulate you after beating Champion's Road. In Bowser's Fury, she became "Mega-Plessie" after consuming 3 Giga-Bells.
You control Plessie by using the joystick on the gamepad, or arrow keys. and A/2 to jump. When two players, you can decide if one person can make her move, and the other can make her jump. Or only one person controls.
In Bowser's Fury, She is controlled by using B/A to jump, and Y/X to dive underwater. If you jump after diving Plessie will jump higher than usual, but you must time it correctly. She can be dismounted with ZL/ZR.