Mysterious and nefarious intelligence floating through space, the Great Intelligence had at first a penchant for mechanical yetis, which we greatly miss in New Who. The Great Intelligence would eventually inhabit many forms and enlist the services of many a creature to battle its nemesis, The Doctor. In New Who, the Great Intelligence was played by Richard E Grant, Withnail himself!
The Great Intelligence employs those chaps from Buffy and a Back-To-The-Future letter to lure The Doctor to Trenzalore
Definitely-not-a-monk invites newish companion Clara Oswald into his snog box
Mary Poppins moonlights as Eliza Doolittle and The Great Intelligence feeds countless labourers to his carnivorous snowmen
The epic return of two foes and introduction of a lifelong friend and ally