Vinvocci

The Vinvocci were the race that created the Immortality Gate.

Biology
The Vinvocci were green, spiky humanoids. They resembled the Zocci, but were taller.

Technology
The Vinvocci used shimmers to appear as humans.

History
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 get the Gate mended, but The Master stopped their plans by using it himself. (DW: The End of Time)