The Tar-Modowk were a race that fed on time.
The Tar Modowk evolved from the Meg-bania and were especially drawn to temporal anomalies. They were roughly humanoid and were much larger than humans. The Eighth Doctor's companion Lucie Miller described the Tar Modowk leader as "a bulking, great thing." (AUDIO: No More Lies)
Time loops eroded the barriers between the universe and the Time Vortex, allowing the Tar Modowk into the universe. The Tar Modowk spent aeons trying to find some trace of their previous existence. The Tar Modowk eventually found Nick Zimmerman's Meg-bania ship in the time vortex and tried to claim it for themselves. (AUDIO: No More Lies)