Many of the show's best cliffhangers revolve around the shocking return of a character or an unexpected plot twist. This one from the Patrick Troughton story The Mind Robber features neither of these but it still managed to surprise viewers by offering a strange dreamlike scene - and one of the most surreal moments in Doctor Who's history. The TARDIS has fallen out of reality and into a black void. As a mental force attacks the Doctor, the time machine breaks apart to leave Jamie and Zoe clinging to the console as it spins deeper into the void before being shrouded in a thick smoke. Very well directed and scored with throbbing, eerie music, this is as psychedelic as 1960s Doctor Who gets. What's more, it made for one of the weirdest Who cliffhangers. Groovy, man!
