PART III. Die Installation Errors:

Mules: 

Regular-issue die muled with government medal or

token die, 2000 Canadian “Map Mule”

Definition: Mules are coins struck by mismatched dies.

The infamous 2000 Canada Millennium “Map mule” falls into this category. A normal commemorative obverse (anvil) die carrying the bust of Elizabeth was paired with a hammer die that was supposed to strike the map-bearing reverse of the Royal Canadian Mint medal that is included in each mint set. Only a few hundred were released.