Vinvocci

The Vinvocci were a species of green skined, spiky humanoids.

Biology
The Vinvocci were green, spiky humanoids. They resembled the Zocci, but were taller and green. (DW: The End of Time)

Technology
The Vinvocci used shimmers to appear as Humans. These devices, disguised as a wristwatch, allowed Rossiter and Addams to work for Joshua Naismith undetected. However the device was uncomfortable to use.

Rossiter and Addams also had a salvage spaceship. It had a teleport system connected to the wristwatches and several sets of automatated laser weapons for destroying asteroids. (DW: The End of Time)

History
In December 2009, a salvage team, consisting of Rossiter and Addams, arrived on Earth in order to find the Immortality Gate. The Gate had been reactivated by humans, which sent out a signal and attracted the pair. They infiltrated the company of Joshua Naismith, under the guise of two Human scientists. They were trying to repair the Gate, but the Master stopped their plans by using it himself, transforming every human on Earth into duplicates of himself. The Vinvocci, unaffected due to their alien nature, helped the Doctor and Wilfred Mott escape the Master, bringing them to their ship, and later helped the Doctor return to the Naismith mansion, dropping off Wilfred shortly after. They then departed, unwilling to involve themselves any further in the conflict. (DW: The End of Time)

Apparently the words "cactus" and "cacti" -- references to an Earth plant of similar appearance -- are considered racist terms by the Vinvocci, as Rossiter indicated when the Doctor used the latter term.

Behind the scenes

 * In the first Doctor Who Confidential episode for DW: The End of Time, Russell T Davies briefly suggests that the Vinvocci and Zocci are in fact related species.