10 Biggest WTF Doctor Who Moments

6. The Death Montage (Heaven Sent)

After watching Clara die in the previous episode, the Doctor finds himself in a mysterious location with no idea how he got there. He's also being pursued by some sort of cloaked monster that can kill with a single touch.

So far, so bizarre.

Throughout Heaven Sent, the Doctor finds out that he's in a Confession Dial, a Time Lord device designed to trap prisoners in a never-ending hell. He eventually figures a way out of the Dial, but only after dying a lot.

Like, really a lot.

Watching the Doctor dragging his dying body through the castle before frazzling his head and killing himself over and over again is heart-racing stuff. The scale and scope of what's going on is mind-boggling, and it speaks volumes to the legendary tenacity that makes the Doctor such a great hero.

Heaven Sent is a WTF episode in general. Not in a bad way or a weird way, like many of the entries on this list - but because of how far it pushed the Doctor and the show itself into territory it rarely ventures.