Vortex Wraith

Vortex Wraiths were a chaotic, quasi-biological life form that was indigenous to the Time Vortex.

History
The Time Lords build defences into their TARDISes to prevent the Wraiths from noticing them. (EDA: The Slow Empire)

After Gallifrey was destroyed, the Wraiths were forced to evacuate the time vortex due to the Council of Eight. (EDA: Anachrophobia)

The Transference network of the Slow Empire once allowed a group of Wraiths to penetrate the Doctor's TARDIS. (EDA: The Slow Empire)