The Trimestrain were an alien race of grey creatures with sharp teeth, long claw-like fingers and red eyes that appeared to be carved from old stone. They were native to Wolanga.
The Tenth Doctor narrowly avoided a trap laid by Bloodgrunge, a Trimestrian Warlord, who was himself killed in it. He left behind a vengeful wife, Jillonga, and two young children, Yanta and Slopp. Jillonga took the children out of school and they travelled to Earth in a journey taking some sixty years in a spaceship that disguised itself as a slightly taller and thinner house on the end of a street in London. They tried to track down the Doctor using a website run by Mickey Smith. Mickey was only just able to escape from the space ship before it left on its flight home. (DWF: The Hero Factor)