From the Super Mario Wiki
Lakitu's Clouds (originally, Jugem's Cloud, "Jugem" being the romanization of Lakitu's Japanese name) are a type of cloud with a smiley face that Lakitus usually inhabit. Lakitus throw Spinies from the cloud. Other cloud-like enemies have appeared in the Mario franchise, such as Ruff Puff, whose Tattle in Super Paper Mario openly speculated on the relationship between it and the similar Lakitu's Cloud.
In Super Mario Bros. 3, Jugem's Cloud could be used by Mario or Luigi to skip a level he did not want to go through (although he would be transported back to the space before the level if he lost a life at the one he skipped to).
In Super Mario World, Super Mario World 2: Yoshi's Island, Yoshi's Island: Super Mario Advance 3, New Super Mario Bros., New Super Mario Bros. Wii, New Super Mario Bros. 2, New Super Mario Bros. U, Yoshi's New Island and Super Mario Maker, after taking out the Lakitu inhabiting it (if there is one), the player can jump on Lakitu's Cloud to reach places that he or she could normally not get to. In New Super Mario Bros. 2, when the player touches a Gold Ring, Lakitus and their clouds become gold. When the player rides on the cloud, it generates coins. In New Super Mario Bros. U, Lakitu's Cloud now mouths to the "bah"s in the music. It also appears in the Challenge Mode level Lakitu's Cloud Heist. In Super Mario Maker, players can shake Lakitus to remove them from their clouds, leaving them for Mario to use or to put other enemies, such as Hammer Bros. or objects, such as Cannons, in them.
Lakitus reappear in Super Mario Galaxy 2 riding their clouds, but these clouds cannot be ridden by Mario or Luigi. If a Lakitu's cloud is eaten, the Lakitu will fall to the ground on its shell and struggle for a few seconds, then a cloud will re-appear and the Lakitu will take to the air again.
Most Lakitu's Clouds are white. However, in Paper Mario, Lakilulu, the girlfriend of Lakilester, has a pink-colored cloud; additionally, the clouds of Dark Lakitus from Paper Mario: The Thousand-Year Door are gray in color. Lakithunder of New Super Mario Bros. also has a dark gray cloud with glaring, yellow eyes; Lakithunder's cloud is capable of firing lightning bolts, as well. Giga Lakitu from Super Mario Galaxy 2, another lightning-firing Lakitu, has a purple cloud. In Mario Kart 7, the cloud also has goggles in seven courses. In Mario Kart 8 Lakitu's Cloud appears on several flags around the course Dragon Driftway.
Most Lakitu's Clouds have faces. In the Paper Mario series, the clouds share the expressions of their owners; additionally, some Lakitu's Clouds in the Paper Mario series wear sunglasses. The clouds of Fishin' Boos and Calm Fishin' Boos do not have faces, however, and in Super Mario 64, The Super Mario Bros. Super Show!, and Super Mario Bros.: Peach-hime Kyushutsu Dai Sakusen!, all Lakitus are portrayed without faces on their clouds. In the latter, Lakitu and Mario are able to control rain, thunder, sun, typhoons, and snow with levers that are on the cloud.
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