Gold Chomp

Gold Chomps are special Chomps in Super Mario Galaxy and Super Mario Galaxy 2.

Super Mario Galaxy
The only Gold Chomp in Super Mario Galaxy appears in the Gusty Garden Galaxy, where it plays a prominent role in the mission The Golden Chomp. It contains a Power Star inside, but Mario is unable to break it open without the use of a Rainbow Star, which can be obtained after collecting a series of ? Coins. This power-up allows the player to destroy the Chomp, revealing the Power Star.

Super Mario Galaxy 2
In Super Mario Galaxy 2, Gold Chomps appear in the Chompworks Galaxy's first mission, Where the Chomps Are Made of Gold. Here, Mario must lead a Gold Chomp from the end of an area all the way back to the front of the area. However, it takes a set route and Mario must alter the area slightly to allow the Gold Chomp to roll to the front of the area and into a hole, where it will break and reveal the Power Star. They reappear in the Chompworks Galaxy's Prankster Comet mission titled Cosmic Clones in the Chompworks, where they serve the same role as before.

Super Mario Odyssey
"It sounds to me like someone wants to be a snack for my adorable Chain Chompikins!"

- Madame Broode

In Super Mario Odyssey, while Gold Chomps are not normally found in the game as enemies, a golden Big Chain Chomp named Chain Chompikins is owned by Madame Broode. It attacks Mario and Cappy by quickly charging towards them and biting, just like normal Chain Chomps, but the outline used to show where it is going is yellow instead of red. It must be captured by Mario to defeat Madame Broode. It is fought again in the Moon Kingdom, where it has multiple hats instead of one hat, making it take longer to capture it. The method of defeating Madame Broode remains unchanged.

Trivia

 * In Super Mario Sunshine, while visiting Pianta Village during the fourth episode in "Chain Chomp's Bath", if Mario drags the Chain Chomp into the tub, it will turn golden and a Shine Sprite will appear from its head.