10 Horror Movie Mysteries That Will Never Leave You

In Denis Villeneuve's Enemy, history professor Adam Bell (Jake Gyllenhaal) is watching a movie when he notices one of the actors, Anthony Claire (also Gyllenhaal), is his exact double. When Adam tracks down Anthony and his wife Helen, he finds his life turning upside down with immediate effect.

While watching a film centred around doppelgängers, many viewers have the same questions. "Are the pair twins?" "Are they clones?" "Is one of them from a parallel universe?"

However, most people won't be concerned with questions like this when it comes to Enemy. When it's all said and done, every viewer has the same lingering thought: "Why are there tarantulas everywhere?"

Even though these spiders appear prominently throughout the story, their relevance is never explained. The most perplexing moment is during the final scene when Adam heads to the hotel which Helen is staying. As Helen walks towards the bedroom, Adam says he's going out, but becomes concerned when she doesn't answer.

As he enters the bedroom, he sees Helen has transformed into a colossal tarantula, who cowers in his presence. Instead of freaking out like a normal person, Adam calmly sighs before the credits roll.

Um... what?