The Great Intelligence is a mysterious, old entity that roams he universe, usually relying on possession of living creatures, taking other shapes, or manipulation of its allies in order to achieve its goals, as it has no physical existence. The Intelligence is very powerful, being able to exert telekinesis and mental control over its victims. The Doctor faced the Intelligence many times, the last time being on Trenzalore, where the Intelligence intended to enter the Doctor’s time stream and turn all the Doctor’s victories into defeats. Its plan was foiled by Clara Oswald, who followed the Intelligence into the Doctor’s time stream and was shattered into millions of echoes that scattered throughout history in order to save Doctor, ultimately undoing any damage done by the Intelligence.