Doctor Who: Last Christmas (2014)
It's a competitive race, but "Last Christmas" has at least got to be in the running as the least rational, most bizarre episode of Doctor Who produced since the show was restarted in 2005. It's essentially a mashup of Aliens, Inception, and The Thing. With Santa Claus. The Jolly Old Elf is played by Nick Frost, who might be the single best named actor to ever take on the role. He does a fantastic job with it, too, embracing the absurdity of a fantasy character showing up on a science fiction show. The opening focuses on Clara, still grieving, rushing to her roof to investigate a loud crash. She discovers Santa Claus and two elves trying to corral their flying reindeer. The TARDIS shows up in the middle of this, and The Doctor appears to trade barbs with Santa before taking Clara away. They soon arrive at the North Pole, where they discover a group of scientists dealing with an alien outbreak. The aliens, called Dream Crabs, are drawn to people who are thinking