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Purple Coins are special Coins that first appeared in Super Mario Galaxy. They only appear in the major galaxies when a Purple Comet is in orbit of a Galaxy. Unlike regular coins, these coins do not restore any of the player's health, or refill the air gauge while underwater.
Super Mario Galaxy
The player always needs to collect 100 Purple Coins to make a Power Star appear. In missions with a time limit, the Purple Coins are sometimes set along a linear path. Other times, more than 100 Purple Coins are scattered in a big area, but the player has to get just 100 coins. Additionally, once the Power Star appears, it has to be grabbed before the remaining time runs out.
In missions that are not timed, the Purple Coins are spread out across the level, requiring the player to explore every area in order to find them all.
All of the timed Purple Coin missions have a background music that is a remix of Gusty Garden Galaxy's theme. The Purple Coin missions of the Battlerock and Dreadnought Galaxies have the same music, even if the missions do not have time limits. This is because Mario collects Purple Coins set in a linear path while riding on moving platforms, and he can't get any coins left behind since the platforms won't backtrack.
Super Mario Galaxy 2
Purple Coins re-appear in Super Mario Galaxy 2. They still appear in Comet missions, but with a small change: the timer stops once the requirements are met. In the Rolling Coaster Galaxy, a Purple Coin will be in a ball, replacing the Star Ball. This is called a Purple Coin Ball. In this game, Player 2 can collect Purple Coins for Player 1 along with regular Coins.
Super Mario Galaxy Trading Card description
Purple Coins are special coins that only appear when a Purple Comet is in orbit of a galaxy. Mario must travel to each of these galaxies, collecting 100 purple coins in each one in order to reveal the Power Star that is hidden there.
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