Doctor Who: Peter Capaldi’s 9 Coolest Stand Alone Episodes

'The moon's an egg.'

That line alone should have killed the episode dead but, if anything, the opposite happened. Equipped with a temporary child assistant, The Doctor and Clara embark on a mission riddled with dilemma, and a story filled with a ruck of substance.

The episode might have been something of a throwaway concept, if it weren't for two things. The first was that Clara was really angry, and the second was that The Doctor was a massive dick. Though attempting to put his comparatively ape-like assistants to rights by leaving them to work out a potentially world-ending decision on their own, the Doctor didn't consider in the running that said assistants weren't appreciative of the gesture. To make the analogy for a second time, it was probably the most Rick Sanchez wed ever seen Capaldi's Doctor.

For this reason, the episode concludes with Clara embarking on a hell-for-leather, outburst against Doc number 12, and it's possibly the most angry and heartfelt companion rant in history. For the first time, we saw Capaldi's incarnation truly stunned, and a little intimidated, hence some great drama.