Reversing matter, also described as "retro-metabolism",[e 2] allows the Mysterons to re-create the likeness of a person or object in the form of a facsimile that is under their control. This ability is used to conduct a "war of nerves" against Earth, in which the Mysterons issue threats against specific targets (from world leaders and military installations to whole cities and continents) and then destroy and reconstruct whatever instruments are required (whether human or object) to execute their plans. The presence of the Mysterons is indicated by two circles of green light (the "Mysteron rings") that trail across scenes of destruction and reconstruction.