Oubliette of Eternity

The Oubliette of Eternity was one of the darkest secrets of the Time Lords' Celestial Intervention Agency.

It was a device installed in a chamber used to disperse criminals convicted of high treason. This was accomplished by supposedly erasing them from history so that they never existed. However, it was used as a method to dispose of Gallifreyans that learnt of its dark secrets. Rather then erase them, it cast them into a Universe filled with Anti-Time and transformed them into Neverpeople. (BFA: Neverland)