Cyberman

The Cybermen are a sapient, spacefaring species of cybernetically-enhanced humanoids which originated on the Earth's twin planet Mondas, and have tried to invade Earth on numerous occasions. Their original form was identical to Earth's Humans, and they can convert Humans into more of their kind.

After Mondas was destroyed in 1986, the surviving Cybermen adopted Telos as their new world, nearly wiping out the native Cryon species in the process.

Biology
The original inhabitants of Mondas have been described as being "exactly like" Earth's Humans, until their scientists realized that their species was getting weaker and their lifespans progressively shorter. As a result, they started to graft themselves with cybernetic implants and gradually converted themselves into biomechanical creatures, retaining their organic brains while replacing almost everything else with robotic parts. Internal organs such as their hearts were scrapped, and even their neural structure was altered to remove their emotions, since they regarded those as a weakness.

The Doctor has claimed on multiple occasions that the Cybermen were originally Human, and while this might not necessarily be the literal truth, it is certainly possible that Mondas, being Earth's twin planet, was also inhabited by Homo sapiens.

Thanks to their biomechanical nature, Cybermen are endowed with the strength of ten men, immunity to disease and resistance to extremes of temperature, being able to survive in the vacuum of space without protection. They feel no pain and require neither food nor air to survive. Their metallic bodies are entirely bulletproof.

Some Cybermen can emit energy beams from their hands that render Humans unconscious, and some can hypnotize Humans by emitting mind-controlling rays from their heads. At least some Cybermen are equipped with in-built energy weapons on their chests which can kill Humans with one shot, while others seem to either lack this capability or prefer to carry hand-held weapons instead for some reason.

Unsurprisingly for a bio-cybernetic species with a long and complex history, Cybermen originating from different times and places often look significantly different from each other, although their basic form tends to remain the same: mechanical humanoids with flat, inexpressive faces, round black orifices for eyes, and tubular handles on the sides of their heads.

Some Cybermen have three digits on each hand, whereas others have five, and some even appear to retain humanoid hands made of flesh. Their bodies are almost always silver in color, but a few exceptions are known to exist, such as a black Cyberman encountered in the London sewers in the year 1985. In this case, it appears the black coloration was chosen to enhance stealth.

Cybermen usually speak with electronic voices, sometimes accompanied by a buzzing sound, and some Cybermen have been observed to speak with a strangely-patterned sing-song-like speech that randomly emphasizes certain syllables. They rarely move their mouths while speaking.

Groups of Cybermen are sometimes led by a Cyber-Controller, whose enlarged heads appear to house a larger and more sophisticated brain. Other groups have been observed to follow orders from a non-humanoid, non-mobile machine known as a Cyber-Planner. It's not known whether Cyber-Planners are computers or have organic brains within them.

In spite of their physical strength and resilience, Cybermen have a number of vulnerabilities. Exposure to sufficiently high doses of radiation will kill them.

Most Cybermen have a deadly weakness to gold. According to the Fourth Doctor, this is because gold is a non-corrodible metal which, when inhaled in powdered form, clings to their breathing apparatus and suffocates them. However, in at least some Cybermen, the allergy to gold is so severe that merely having their chest units pierced by gold objects can be instantly fatal.

In 2070, Ben Jackson and Polly Wright mixed up a combination of solvents, including acetone, benzene, ether and alcohol, to create a "cocktail" that could dissolve the plastic components on a Cyberman's chest unit and fatally damage their internal circuitry.

Being emotionless creatures, the sudden exposure to emotional pulses, such as those generated by Professor Watkins' Cerebration Mentor machine, can be destructive enough to incapacitate Cybermen.

Culture and society
Cybermen consider themselves superior creatures and have no regard for other humanoids, except as potential converts. They have no qualms about deceit and treachery, and will readily disregard previous arrangements and eliminate former allies, as many Humans who tried to ally themselves with them have found out. They consider emotions and compassion to be weaknesses and have ensured that the cyber-conversion process eliminates their own capacity to experience such feelings.

Technology
Over the course of their history, Cybermen have employed several different types of spacecraft, varying in size and shape. The Cybermen who attacked the Moonbase on Luna in 2070 utilized saucer-shaped spacecraft. In most other occasions, they have used more elongated ships, sometimes with wheel-shaped components. Arguably their greatest technological achievement was to convert their entire homeworld of Mondas into a self-propelled planetary body that they were able to move back to the solar system in 1986.

Although at least some Cybermen are known to have the in-built ability to generate energy blasts from their hands, heads or chests, which can stun and even kill Humans, Cyberman troops have often been observed to carry hand-held energy weapons as well. The prevalence of hand-held weaponry suggests that these might be deemed preferable over their in-built offensive arsenal, which might not be present in all models.

A neurotropic viral agent known as "neurotrope x" has been used by Cybermen to infect Humans. The neurotrope attacks the victims' nervous system, facilitating the job of harvesting the victim for cyber-conversion.

Cybermen are also known to employ Cybermats: small biomechanical creatures which range from mouse-sized to rabbit-sized and can perform a variety of functions, such as being programmed to locate a specific target by his or her brainwaves. In spite of their seemingly harmless appearance, Cybermats can jump on a victim's neck and inject toxins directly into their bloodstream.

History
The Cybermen evolved on the planet Mondas, Earth's twin planet, with a continental arrangement similar to Earth's but inverted. Millions of years ago, Mondas drifted away from its original orbit and out towards deep space, leaving the Sol System behind. The Mondasian civilization developed similarly to Earth, but became much more advanced, culminating in the creation of the Cybermen.

At some point in the late 1960s, the Cybermen attempted to invade Earth by operating from the dark side of Luna and enlisting the help of Human business magnate Tobias Vaughn, head of International Electromatics, who used his company's resources to pave the way for the invasion while taking instructions from a Cyber-Planner. The Cyber-Planner recognized the Second Doctor and Jamie McCrimmon, who had been encountered before on "planet 14", and deemed them a threat to the Cybermen. Ultimately, the Doctor managed to convince Vaughn to turn against his treacherous allies, who were defeated with the help of the newly-formed United Nations Intelligence Taskforce (UNIT). It's not clear whether "planet 14" refers to Mondas or to another world colonized by Cybermen.

In 1986, what appeared to be a new planet approaching Earth turned out to be the Cybermen's homeworld of Mondas, heading back to its original orbit. A small group of Cybermen landed in Antarctica and took over Snowcap Base. Fortunately for humanity, the Cybermen's attempt to drain the Earth's energy and redirect it to Mondas accidentally resulted in an overload that destroyed Mondas along with the invading aliens.

After Mondas was destroyed, the surviving Cybermen colonized Telos, decimating the native Cryons in the process. The planet was chosen for its refrigerated cities, deemed ideal for the Cybermen to hibernate and replenish their (at this point dangerously low) power. At some point in the future, a group of Telosian Cybermen gained access to time travel and attempted to destroy Earth in 1985 to prevent the fiasco that would result in Mondas' destruction in 1986. This time their plans were thwarted by the Sixth Doctor.

In 1988, a small-scale invasion took place by a group of Cybermen looking for the Nemesis: a living Gallifreyan statue made of validium with almost unlimited powers, which the Cybermen planned to use to convert Earth into a New Mondas. Instead, the Cyber Fleet was destroyed by the Nemesis.

In 2070, a group of Cybermen took control of the Moonbase hoping to wreak havoc on the Earth's weather patterns with the base's Gravitron system used for meteorological control. This was not the only incident that occurred in the late 21st century: a few years later the Cybermen, led by a Cyber-Planner, managed to successfully infiltrate Space Station W3. In both the Moonbase incident and the Station W3 incident, the Cybermen were defeated by the Second Doctor and his companions.

At some point in the future, a devastating Cyber War took place, in which Humans emerged victorious thanks in part to the invention of the glitter-guns to fight off the Cybermen, using powdered gold-based ammunition to poison their circuitry. This resulted in severe losses for the Cybermen, reducing them to scattered nomadic groups operating on obsolete ships. Centuries later, one such Cyberman group attempted to destroy the gold-rich planetoid Voga to cut off humanity's supply of gold.

In 2526, the Cybermen planned to detonate an explosive device on Earth while an interplanetary conference took place, in which the leaders of several planets would sign a pact to unite their military forces in a new war against the Cybermen. When that plan failed, they sent a freighter ship to crash into Earth, hoping to achieve the same result. Instead, the freighter was transported back in time over 65 million years and collided with Earth as intended, provoking the mass extinction of the dinosaurs (and ironically paving the way to the eventual rise of humanity as the planet's next dominant species). As predicted, the Great Orion Cyber Wars of the 26th century resulted in the Cybermen's defeat and apparent extinction.

Cyberman tombs were discovered on Telos long after the Cybermen were deemed extinct, much to the enthusiasm of archaeologists. The Cybermen encountered on the planet Chronos in 3286 believed themselves to be the last members of the species. By the time of the Galactic Federation, there had been more than one "Cyber-fad" among archaeological researchers, apparently comparable to the Egyptomania of 19th century Earth.

At an unspecified point in history, a Cyberman was one of the many creatures miniaturized and trapped inside a miniscope by the Lurman showman Vorg.

When the Second Doctor was put on trial by the Time Lords, facing charges of disregarding the law of non-interference, he listed the Cybermen, along with the Daleks and the Ice Warriors, as examples of hostile species that had tried to conquer Earth and had to be stopped.

A group of Cybermen figured among the Doctor's enemies transported to the Death Zone of Gallifrey by President Borusa along with multiple incarnations of the Doctor himself and some of his companions.

Alternate timelines
In a divergent timeline resulting from a temporal paradox, the Cybermen conquered Earth in the year 1927 by releasing a nanotechnological virus that could convert organic tissues directly into mechanical parts. Most animal life, including a large portion of the Human population perished, and the few survivors were rendered almost entirely robotic.

Knowing that the Cybermen had traveled back in time to introduce the virus, Reece Goddard traveled to the year 3286 and tried to destroy them by using a modified version which would have the reverse effect, converting metal into flesh. Ironically, Goddard's virus actually provided the template for the Cybermen to produce the original virus, creating a temporal loop.

Appearances

 * Doctor Who
 * Season 4, The Tenth Planet (1966)
 * Season 4, The Moonbase (1967)
 * Season 5, The Tomb of the Cybermen (1967)
 * Season 5, The Wheel in Space (1968)
 * Season 6, The Invasion (1968)
 * Season 10, Carnival of Monsters (1973)
 * Season 12, Revenge of the Cybermen (1975)
 * Season 19, Earthshock (1982)
 * The Five Doctors (1983)
 * Season 22, Attack of the Cybermen (1985)
 * Season 25, Silver Nemesis (1988)
 * Dimensions in Time (1993)
 * Real Time (2002)

Alternate universes
In a parallel universe, Cybermen were created on Earth in the early 21st century by John Lumic, head of Cybus Industries.