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 Red Luma 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.

Power-ups in the Super Mario Bros. series

Mushrooms: Super Mushroom | Mini Mushroom | Mega Mushroom | Poison Mushroom | Boo Mushroom Bee Mushroom | Propeller Mushroom | Spring Mushroom | Rock Mushroom | Acorn Mushroom Flowers: Fire Flower | Ice Flower | Cloud Flower Caps: Metal Cap | Vanish Cap | Wing Cap Suits: Hammer Suit | Penguin Suit | Frog Suit | Tanooki Suit | Flying Squirrel Mario Yoshi: Yoshi | Bulb Yoshi | Blimp Yoshi | Dash Yoshi Misc: Super Leaf | P-Wing | Cape Feather | P-Balloon | Starman | Blue Shell | Red Star | Spin Drill