Star Coin Sign
From the Super Mario Wiki
A Star Coin Sign is a wooden sign blocking a path on the world maps in New Super Mario Bros.. They cost five Star Coins to remove, and doing so opens up either a Toad House or an alternate level. Players can save after opening one. Star Coin Signs are found in every world, some containing more signs that others, allowing access to more Toad Houses and/or extra levels.
Posts like this also appear in New Super Mario Bros. Wii. They are only located in World 9, and block all eight of the levels. The only way to get them to disappear is to collect every Star Coin from the world corresponding to the level in World 9 (i.e. World 1 opens 9-1, etc.)
Star Coin Signs reappear in New Super Mario Bros. 2, serving the same purpose as in the first game. One Star Coin Sign and the Golden Toad House appear in World Star after collecting all Moon Coins. The sign blocking the Golden Toad House can be removed by paying nine Star Coins.
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