Red Stars are power-ups in Super Mario Galaxy. Red Stars transform Mario into Flying Mario. Theywear off over time, and are only found in the second mission of the Gateway Galaxy and specific spots of the Comet Observatory. They are unlocked for use in the Observatory after Mario obtains the Red Power Star in the second mission of the Gateway Galaxy. In this mission, Mario must collect one hundred Purple Coins for the RedLuma to activate Red Stars. Its ability also appears in Super Mario Galaxy 2 through hacking, but the ability is never used, nor is it seen in the game. The Red Star itself never appears in the game.
It also appears in Super Mario 64 intro,but it can't be used and you cant catch it.