It's the SMA4 Ace Coin, but recreated pixel by pixel on SMW! This works as a replacement to the original Dragon Coins. This is designed for hacks that would rather had a generic big collectible rather than a Dragon or Peach.
Now with support for Erik's New Super Mario Bros. Wii Styled Status Bar! Here: https://www.smwcentral.net/?p=section&a=details&id=14775