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The 100 Gold Coin is a special kind of Coin that first appeared in the Wario games and later in Mario games. Although their appearance varies between the different installments, these rare coins have one thing in common: They add one-hundred regular coins to the player's coin counter. Other coins existing for the main purpose of increasing the player's coin counter by more than one unit are the 10 Gold Coin and also the Blue Coin featured in the Mario series.
Wario Land series
Wario Land: Super Mario Land 3
Wario discovers a 100 Gold Coin in a secret room in Wario Land: Super Mario Land 3
100 Gold Coins make their debut appearance in the game Wario Land: Super Mario Land 3. They look similar to regular coins, but are four times bigger and bounce in place. Unlike their smaller counterparts and 10 Gold Coins, 100 Gold Coins are very rare and usually well hidden. They are located in specific levels and can be obtained by hitting a giant Face Block. Since they add many coins to Wario's coin counter, they can be valuable when Wario makes his wish to Denpuu at the end of the game.
Wario Land II
A 100 Gold Coin in Wario Land II
100 Gold Coins reappear in Wario Land II, where they serve the same purpose as in the previous installment of the Wario Land series. They look like regular coins, but are silver in color and flash rapidly. They also produce a characteristic noise once they appear and when they are collected. 100 Gold Coins can be found by breaking objects or defeating enemies, just like regular coins. It appears every 64th time either of the previous actions is taken. The Giant Spear Man also leaves a 100 Gold Coin behind every time he is defeated.
Mario & Luigi series
100 Gold Coins also appear in Mario & Luigi: Partners in Time. They are extremely rare and are only found in ? Blocks in the ground via wide trunks where only the baby brothers can go through. Like with the Wario Land series, 100 Gold Coin appear as large gold coins, but this time with the number "100" printed on them. After they are released, they come up to the surface for the Mario Bros. to collect. If they are not collected after a period of time, they disappear.
They later appear in Mario & Luigi: Bowser's Inside Story. Unlike in the previous game, they can be found inside any Question Blocks, but can be found more commonly toward the end of the game. They may also be collected when Bowser defeats a Metal Mawful Mole on the map.
New Super Mario Bros. 2
A 100 Gold Coin in New Super Mario Bros. 2
100 Gold Coins make an appearance in New Super Mario Bros. 2 and are found in the rainbow levels. They appear by flying across the screen as Mario progresses through the area. They are a little bigger than Mario this time, are golden and have the number "100" shown on each side, almost identical to the ones from Mario & Luigi: Partners in Time. They are worth one hundred coins and therefore reward the player with an extra life. 100 Gold Coins can also be found in larger Coin Roulette Blocks.