10 Doctor Who Episodes You Didn’t Know Were Connected
2. The Web Of Fear & The Snowmen
Back to The Great Intelligence now, and his second-ever appearance in the show in 1968's The Web of Fear.
The Intelligence had already encountered the Second Doctor when it lured him and his companions into the London Underground, where it planned to steal the Time Lord's knowledge.
Fast forward to the 2012 Christmas special The Snowmen, and the Doctor runs into the Intelligence once again - only this time, before the villain has met him.
In order to preserve the timeline, the Doctor decides to influence future events (or past events from his point of view) in a way only he could - by using a biscuit tin.
He presents his foe with a tin bearing the London Underground map on it. The Great Intelligence remarks that it's never seen these symbols before, at which point, the Doctor sows the seeds for The Web of Fear by saying that it's a "key strategic weakness in metropolitan living".
With the timeline now assured, the Doctor runs off to celebrate - presumably with a biscuit.