The Arc Ray Cannon is a weapon technology based on creating an Ætheric channel that allows focusing an electric discharge against a single target at extremely a long range (for an electrical attack).
A firing ARC looks exactly as it sounds - like an electric arc following a ray; sometimes this ray is actually arched, completing the recursive acronym with a pun. (Ray curvature adjustment is part of the ways in which ARC targeting is handled; it provides modest over-horizon capability.)
Stats[]
The ARC itself has the stats of a Lightning Cannon from GURPS Spaceships 7, but the ranges are ten times shorter.