Comet Medal

Comet Metals are a type of item that is going to appear in the upcoming Super Mario Galaxy 2. They appear to be white octagonal coins with a golden lining and a picture of a golden comet (a Star with a tail) imprinted in them. Comet Metals unlock newer and harder levels, similar to the Star Coins in New Super Mario Bros. and New Super Mario Bros. Wii. Comet Metals are found in every galaxy. However, Comet Metals are usually found in hard to reach places. <!-- Please provide a source that actually says that "Flip-Swap Galaxy" is unlocked via Comet Metals".

Trivia

 * When collected, the Comet Metal makes a similar sound effect to that of a Red Coin from Super Mario Sunshine.