Cuculus

The Cuculus were a species of bird-like aliens. They were known to possess the inhabitants of planets, replacing their minds with Cuculus minds.

Technology
The Cuculus used purple, egg-shaped ships to travel in. They used a psychic crystal to implant their minds in other species, giving them glowing purple eyes. The Cuculus were also known for their skills in locks and imprisonment, using deadlock seals. (PROSE: Houdini and The Space Cuckoos)

History
In 1920, the Cuculus invaded Earth, starting with New York City. The Eleventh Doctor was there to stop them, though he wanted the help of Harry Houdini for his escape skills. (PROSE: Houdini and The Space Cuckoos)