Arcateenian

The Arcateenians were a race of humanoids from Arcateen V.

Biology
Arcateenians were made mostly of liquid, (TV: Cyberwoman) yet adopted a humanoid form. To maintain their shape on any planet with a stronger gravitational field than their own, they required large amounts of energy. (TV: Greeks Bearing Gifts) Their internal structure could be seen faintly through their skin. They had tendril "hair" on the top of their head and on their backs. They had five long, slender fingers and a blue tint to their skin, although their aura gave off colours that were invisible to the Human eye. (WEB: Sarah Jane Smith website)

Mary, an Arcateenian, was shown to have super-speed and strength, telepathy, and the ability to inhabit the body of a human. (TV: Greeks Bearing Gifts)


 * Whether all Butterfly People had these abilities or whether these abilities were technology based is unknown.



Technology
The Arcateenians had faster-than-light travel capabilities, including transporter systems and superluminal communications technology. (TV: Greeks Bearing Gifts, TV: Invasion of the Bane) They had developed this by, at the latest, the early 1800s. (TV: Greeks Bearing Gifts)


 * Sarah Jane Smith's friend, the star poet, appeared to have wings and did not seem to use a transporter, but when leaving simply flew away into the night sky.



History
In the early 1800s, a criminal Butterfly Person was sent to Earth with her jailer. She killed the jailer and took over the body of a passing human. She continued to live on Earth for 200 years by feeding on the hearts of other humans. According to her, at that point in time her planet was run by an oppressive government which forced worship and exiled prisoners like herself. (TV: Greeks Bearing Gifts)


 * Mary may have been lying about Arcateen's history.

By the 21st century, there appeared to be a benevolent government on Arcateen V, and peaceful star poets from the planet would travel to other star systems with their poetry. One such traveller met Sarah Jane Smith and gave her a superluminal communications device. (TV: Invasion of the Bane)

In 2007, an Arkan leisure cruiser was spotted flying above Cardiff, and was filmed by some people on their mobile phones, allowing Torchwood Three to identify it. The Arkans were politely persuaded to leave by the institute. (TV: Cyberwoman)

Later that year, Torchwood dug up an Arcateenian prison transport. The criminal previously incarcerated inside tried to infiltrate the Torchwood base to get it back, using Toshiko Sato to do so. She was able to do so, but Jack Harkness had reprogrammed it, causing it to teleport into the sun. (TV: Greeks Bearing Gifts)

Other references

 * Mr Smith had records of the Arcateenians. (TV: Revenge of the Slitheen)
 * John Hart knew an Arkan trick of hiding objects in the lining of the throat. (TV: Kiss Kiss, Bang Bang)
 * Torchwood Three had Arcateenian medicine, but were unsure of its effects on humans. (PROSE: Something in the Water)
 * Henry Parker had a copy of The Fog by James Herbert translated into Arcateenian. (TV: A Day in the Death, WEB: torchwood.org.uk)

Behind the scenes
According to the non-narrative source REF: The Torchwood Archives An Arcateenian's skill-set varied depending on which planet it hailed from. Arcateen IV was the main seat of government in the system. Arcateenians from this planet developed a way with words, although this often worked against them as they could occasionally take up to eight hours to complete a conversation. At the other end of the scale, Arcateenians from Arcateen V developed a concise and poetic way with words, meaning they were often very creative.

Butterfly People are also one of the few aliens to have appeared in both spin-off shows of Doctor Who, but not the parent show itself.