10 Insane Doctor Who Episodes That Almost Happened

There's something really terrifying about not knowing who the enemy is. Movies like The Thing play with this concept really well, with a group of individuals slowly being infiltrated and killed by a shape-shifting creature. It's just an inherently creepy idea: the fear of the unknown, of not knowing who you can trust.

Doctor Who almost did something like this in the early 1970s, with scrapped story The Shape of Terror. This adventure would've featured a shape-shifting villain called the Energid, which faces off against the Third Doctor, his companion Jo, and a group of disposable side characters inside a deserted research base. This story was pitched years before the Zygons (also shape-shifting villains) were introduced, and due to its ability to absorb people's brains, the Energid is a much more powerful and much more evil entity, possibly giving the story a strong horror vibe.

The story was set to conclude with the Energid attempting to merge with the Doctor, who would've then - rather cleverly - tapped into the minds of the people the creature had previously consumed, using their combined power to defeat this nasty alien.

The Shape of Terror was abandoned in the end, although certain elements were later incorporated into the Third Doctor story The Curse of Peladon.