Revenant (ghost)

A Revenant, in human folklore, is a visible ghost or a corpse that had been believed to have been reanimated for the purpose of terrorizing the living. Revenant is derived from the French word revenir - which means, "to return" in that language.

After being murdered by the malevolent being 0, the corpse of Ensign Clarze was turned into a revenant by 0. The revenant then took control of conn before being vaporized by Captain Picard once 0 and Q had left the bridge.