Khlecht

From Tardis Wiki, the free Doctor Who reference

The Khlecht were a race of space-faring asset strippers. Their biology was composed of many arms, many legs, and darkness where their eyes should be. They formed the Khlecht Entity, Inc. and were known across the galaxies for their ruthless efficiency.

They were able to time travel and used organic technology, at least in the bombs they left behind them: their ideology was, "We don't just leave a place the way we found it; we make it better."

The Khlecht were one of the many races that came to 1945 Dusseldorf in search of the persuasion machine. They even bought other species in order to get it. Based on their recordings, they may have been somewhat humanoid and spoke with cheerful voices. (AUDIO: Persuasion)