Golden Mushroom is an item obtainable in a number of Mario games including Mario & Luigi: Superstar Saga, parts of the Mario Kart series, and parts of the Mario Party series. In games of the Mario Kart series, its function is as a boost; as opposed to the Super Mushroom, it allows the player to boost as many times as required or wanted throughout the duration of its existence. In Mario Kart: Double Dash!!, it is Toad and Toadette's special item under the name Super Mushroom.
Mario Kart series
In relation to Mario Kart, a Golden Mushroom is an item that gives the kart continuous bursts of speed over a time period of around eight seconds. A particular Mushroom known as the Golden Mushroom can also be used over and over. In tracks with lots of off-road areas, this item can be a lifesaver, as it allows a racer to traverse terrain at full speed that would slow others down; creative racers can make effective pseudo-shortcuts. This can also be accomplished with a Star or a Mega Mushroom. Sometimes it is necessary to clear some optional jumps. Hitting another player during the boost allows players to steal any items (or balloons in Balloon Battle mode) in Mario Kart: Double Dash!!. If both characters have items, then the player will steal the rear character's item and have the front one drop their item. This is Toad's and Toadette's special item in Mario Kart: Double Dash!!. It also appears in Mario Kart 64, Mario Kart DS, Mario Kart Wii, , Mario Kart 7, Mario Kart 8, and Mario Kart 8 Deluxe.
They appear in New Super Mario Bros. 2, and are worth 50 coins (100 coins if collected as Gold Mario) each. In Coin Rush mode, all 1-Up Mushrooms are replaced with gold mushrooms. There is also a downloadable 'Gold Mushroom Pack' that contains many gold mushrooms.