Clampy

Clampies (also known as Giant Clams or simply Clams ) are giant clam enemies that debuted in Super Mario Galaxy. They open and close their valves periodically, often revealing items which sit inside their cavities. The player can collect these items and swim away before getting caught inside the Clampy as it closes its valves.

Super Mario Galaxy
One cream-colored Clampy first appears in Super Mario Galaxy, being encountered in the Beach Bowl Galaxy. Much like the Clams in Super Mario 64, it holds treasures inside such as Star Chips and Coins.

New Super Mario Bros. Wii
Clampies make their first 2D appearance in New Super Mario Bros. Wii, only appearing in World 1-4 and in a secret area in World 4-1. They now display a purple coloration, which would stick to them in most future appearances. They have Coins or 1-Up Mushrooms between their valves in order to lure a character close so they can attack them. If a Clampy closes its shell in on a character, it will trap them inside for a brief moment and damage them before opening back up. However, their top shells (when closed) and the inside of their cavities (when open) are safe to tread on. In general, Clampies spawn in mid-water and slowly sink to a ground underneath, after which they begin their routine of opening and closing their valves. One Clampy in World 1-4 slips into a pit after touching the ground.

Super Mario Galaxy 2
A single Clampy appears in Super Mario Galaxy 2, behaving and looking identically to the species' initial appearance in Super Mario Galaxy. It appears on the seabed in Starshine Beach Galaxy.

New Super Mario Bros. U
Clampies also appear in New Super Mario Bros. U where they act exactly like they do in New Super Mario Bros. Wii. One can be found in a secret area of Waterspout Beach, while multiple inhabit.

Mario Kart 7
Clampies appear in the Cheep Cheep Lagoon and Daisy Cruiser racecourses in Mario Kart 7. They are obstacles that are found only underwater, containing Coins and Item Boxes between their valves that racers can pick up, taking care not to be trapped by the Clampy's valves. Racers can perform tricks on them when they are open.

Mario Party 10
Clampies reappear in Mario Party 10 in the background of the board Whimsical Waters. They also appear in the minigame Cheep Cheep Check, where they are used by the solo player to disperse large clusters of bubbles meant to distract the other players from counting the Cheep Cheeps.