Pentagon takes cue from Arthur C. Clarke superweapon
New Scientist reports that the Pentagon's Defense Advanced Research Projects Agency (DARPA) is working on a new super-weapon with an eerie familiarity to the Stiletto, a weapon from Arthur C. Clarke's 1955 novel Earthlight: a "solid bar of light" driven by giant capacitors that pierces through spaceships like "an entomologist [piercing] a butterfly with a pin."
Using magnetic fields it will propel either a narrow jet of molten metal or a chunk of molten metal that morphs into an aerodynamic slug during flight. Unlike Clarke's Stiletto, they will come from a device that generates a powerful electromagnetic field from an explosion, not giant capacitors.
DARPA's little gem is called MAHEM and would be used largely against tanks and incoming missiles. Also, the Covenant, whenever they get here.
Science fiction inspires DARPA weapon [New Scientist]

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While the bulk of weapons systems presently under development are based on Clarke's story "Superiority".
This honestly isn't that much different than how explosively formed weapons work today. Everybody remember the weapons Iran was accused of suppling to Iraq to attack Humvees? Same principle, heave a rocket near the target, then detonate the rocket's warhead to sling a molten chunk of copper through the armor.
A railgun driving an explosively formed penetrator? Yawn. Now if they can get the radios to work...