Hidden Coin

Hidden Coins (also known as Dash Coins ) are special types of coins that have been seen in the New Super Mario Bros. games, Yoshi's New Island and Super Mario Run. Hidden Coins are somewhat rare, and only appear in a few levels.

Hidden Coins first appear as an outline of a Coin; if Mario or another character passes through the outline, it will then turn into a regular coin after a moment.

Super Mario Run
Hidden coins are once again found in Super Mario Run, making their first appearance in Ghost-Door Deception. This time, they appear more often than they do in New Super Mario Bros. Wii. Touching them can reveal a regular Coin, a Pink Coin, a Purple Coin, or a Black Coin, depending on the stage or level.