Ocranhos

Ocrhanos
The Ocrhanos were a race of insectoids, they could steal the time signature of other beings, which killed their prey (A World Of Water)

Appearance
The Ocrhanos looked like giant water bugs, they had an organ that looked like a spiral of steel shaped into a ball, they could steal the time signature of beings with this organ, it was close to their mouth, and they could remove it

History
The Ocrhanos were first known to the Time Lords, they destroyed all of them, except for a colony on Hope 332.

The Doctor and Susan found this colony after they had killed some of the crew on The Remembrance Of Dreams, the remaining crew was evacuated, and the remaining escape pod was sent into the colony.