Zagreus

Zagreus sits inside your head. Zagreus lives among the dead… Zagreus sees you in your bed And eats you when you're sleeping.

Zagreus was a Monster in a Gallifreyan nursery rhyme. The Neverpeople, led by Sentris, created a story of Rassilon travelling to the Antiverse as part of a plot to destroy the Web of Time. However when the Eighth Doctor was infected by anti-time he called himself Zagreus. This was a plot by Rassilon to destroy the Divergence. But Zagreus was able to defeat Rassilon.