A coin 32x32 in size in the form of a sprite. It's pretty easy to customise it into another collectable too. Must provide your own graphics.
(Small change by Rykon-V73): The original sprite used tiles that had to be modified a bit and it was on SP4. Now the SP4 version uses the unused GFX from GFX02 and there's an SP3 version that overwrites the Amazin' Flyin' Hammer Bro GFX and fish GFX. Also, converted the sprite to .json and added the SP3 version and converted that to .json. Also, changed the palette to A, since the bonus coin worked great with that palette. You can edit the tilemap and sound effect.
While it works, I have one question, and one question only: Why do you have this necessity of duplicating (or more) the same code essentially, so you waste more sprite slots given you could, in this case specifically, adapt only one code using the extra bit so you had the same result? Please, you either provide only the .json as update (it will be accepted if the sprite still works and the .json is operational) or adapt these kinds of changes without having the necessity of uploading two or more of the essentially the same code. Otherwise, submissions like this one are more prone to be rejected.