Yoshi's Island (SSB)
Visually, the stage looks like it's made of cardboard. The main platform is an open book, and as such it has a V shape instead of being completely flat. Over the main platform hover three soft platforms; the bottom two slightly slope inwards, while the top one is flat.
In the sky surrounding the main stage float three clouds, one on the left side and two on the right. After standing on a cloud for about four seconds it will disappear; this can be prevented by repeatedly jumping instead of standing continuously on it. Disappeared clouds reappear after seven more seconds. Message Blocks hover in the background above the clouds, but they have no gameplay effect.
In both Smash 64 and Melee Yoshi's Island is banned, primarily because the clouds can promote camping. In particular, the rightmost cloud is very far from the stage and is a very powerful camping spot; additionally, some characters such as Link in Smash 64 are unable to make it back to the stage from said cloud.
This stage and its aesthetics are inspired by Yoshi's Story. In that game, Baby Bowser has turned Yoshi's Island in a storybook and stolen the Super Happy Tree, the magical tree which also appears in this stage's background.
Yoshi's Story features clouds that can be used as platforms, some of which have to be activated by pressing a switch and disappear when the switch's timer runs out. However, their design is different from the ones in this stage.