The Saiph

 was a gestalt race that came from the constellation of Orion.

Biology
The Saiph could generate parasites that could change people's personalities momentarily. They were able to turn into protoplasm.

History
The Saiph attempted to invade Earth in the year 1929. The Fourth Doctor and Romana I met them at Antibes. They stole personal items from the hotel at which the Doctor and Romana stayed. (AUDIO: The Stealers from Saiph)