10 Most Chilling Doctor Who Moments
9. Android Sarah Jane (The Android Invasion)
The Android Invasion is full of strange and creepy moments. From the UNIT soldier nonchalantly walking off a cliff in front of a horrified Sarah Jane and the Doctor, to the truck full of mindless drones being driven into the village, it's an underrated gem from the Tom Baker era.
But the most memorable and properly chilling moment in the whole serial is when the Fourth Doctor realises that Sarah Jane has been replaced by an android.
It's such a great ending to the episode, from the Doctor offering Sarah some ginger pop and realising she's been replaced, to him throwing her to the ground where her face falls off. The unnatural way that this Sarah-droid rolls across the grass further adds to the unsettling tone of the cliffhanger.
It's even more impressive because the android facade should be utterly ridiculous – two eyeballs fixed in some plastic cogs and motors. And yet, the image of that android dressed in Sarah Jane's costume is proper nightmare fuel. If we can't trust Sarah Jane Smith, then who can we trust?!
It's an iconic moment, and one that must have left its mark on Steven Moffat. The scene in The Almost People where the Eleventh Doctor melts Ganger Amy Pond surely owes a debt to the Fourth Doctor and Android Sarah.