ricwaters

I hope someone can explain what I've found. The coin is struck with the reverse on both sides (double-tailed), so it has no date stamp or mint mark. The sides are offset by about 90 degrees (a quarter turn). It has clearly been circulated, as I received it in charge at a local store. I only became aware of it because a vending machine wouldn't take it (which I assume means that the weight is wrong). The condition could best be described as "good." Since there are no reports on the Web for double-tailed nickels, I'm wondering if this is a "mule" or some sort of counterfeit. Any help in figuring out what this is will be appreciated. Thank you!