Wing Mario Over the Rainbow

Wing Mario Over the Rainbow is one of three secret levels in Super Mario 64, where Mario uses the Wing Cap to collect eight Red Coins and get a Power Star. The entrance to the level is found in a niche high up the left wall on the third floor of Princess Peach's Castle, opposite of the entrance to Rainbow Ride. The level contains two platforms with a Cannon on each and four solid clouds, which are connected by rainbows. Two of the clouds are transparent and Mario can fly straight through them. There are six red ! Blocks strategically placed around the level, making it easy for Mario to get from one cloud to another. If Mario falls from the level, he will not die, but will rather land in the pond outside Princess Peach's Castle. A Bob-omb Buddy appears in this level, and Mario has to talk to him to open the Cannons. This is the only secret level that features the use of Cannons. In Super Mario 64 DS, this level was retitled Over the Rainbows.

Star 1
Using the Wing Cap and cannons, Mario must fly around the level and collect the eight Red Coins to make a Power Star appear.

Star 2 (DS only)
A black Brick Block can be found on one of the clouds. If Wario can get to the block (either by long jumping or use of a Cannon), he can break it to earn a Power Star.

Trivia
This is the only course that doesn't have Luigi's cap even when he's unlocked.