The Mysterons are a race of disembodied entities from the television series Captain Scarlet And The Mysterons. They have no known physical identity, their only form of appearance being through two green rings. They are capable of communicating in English with Humans, via radio and other means.
They have perfected the ability to reverse matter (also known as Retro-Metabolism), which is demonstrated when Captain Black destroys their Martian Complex after mistaking a surveillance camera for a weapon and concluding that they are under attack. Having destroyed the city, the Mysterons rebuild it in a matter of seconds before declaring a War of Nerves against Earth for the unprovoked attack, vowing that they will destroy all life across the planet. They took control of Black's mind making him their official Earth based agent
The Mysterons have the ability to use their powers of retrometablism to re-create an exact likeness of any object or person and use them to achieve their aim. Their threats have included killing members of state, wiping out cities and even stopping Spectrum from countering their attacks.
A Mysteron city was located on the far side of Mars, away from visible sight. The city was discovered by Spectrum in 2068, after mysterious signals had been traced back on Earth.