The original 8-bit Super Mario mushroom ready to print for your key chain.
It prints in multiple sections that snap together. This way you can print the appropriate colors for each section. I recommend you print the "outline" in black and the "white inserts" as white. But then choose your own color for the "color insert." Red for a growth mushroom, green for a 1-up, etc.
Personally, I had to use a hammer or a vice to snap everything together. If instead it is too loose, then just paste a layer of super glue over both sides.