10 Dropped Doctor Who Plot Threads We'll Never Get Answers To

10. The Truth Behind The Midnight Entity

One of the most chilling episodes in Doctor Who history, Series 4's Midnight pits the Doctor against a terrifying, powerful - and most importantly - unseen enemy.

The Midnight entity approaches the Doctor (and a group of citizens) while he's trapped inside a broken-down tour bus, and is somehow able to enter said bus without any of its passengers noticing, and without leaving a single trace of damage. It then stealthily possesses people, never showing its true form.

While the entity is seemingly vanquished at the end of the episode - and even that isn't a sure thing - it remains one of the only monsters in the universe that the Doctor knows nothing about, and we haven't seen it in another episode since Series 4 aired.

So what exactly is the Midnight entity? What does it look like? Are there more?

While there have been plenty of theories suggested by fans, we don't know the answers to any of these questions, which is unusual because Doctor Who, normally, does at least do some explaining about its bad guys.

That being said, the episode was clearly deliberately designed to reveal as little information as possible, and the lack of details about the entity only enhances the suspense. So it wouldn't be a total tragedy if it went unexplained permanently.