A Mobius blade was a hand held weapon that was needle shaped. Use of the weapon meant that it had to be pressed near the target's flesh at which point nanomolecular arms would be propelled into the body that would generate painful currents into the body. This was a particularly cruel weapon that would literally carve its way through a victim's internal organs.

In the mirror universe, Commandant William T. Riker wielded such a weapon. (Star Trek novel: Dark Victory)