The Totem of Nehual is something of a Maltese Falcon. Many have spent long periods of their life searching for it, spending vast sums of money, and in the end never finding it, or only finding it long enough to lose it.
For a futuristic grim gory setting. Probably powered by some kind of dilithium battery or something similarly awesome. Anyways, basicly a big drill sticking up from a hilt that you primarily use for skewering enemies painfully and drilling through armor.