3. Valak, Valak Everywhere - The Conjuring 2
Valak is the name of the demonic entity terrorising a London family in The Conjuring 2, and director James Wan ensured to include references to the demon throughout the movie.
Valak's name is written four times during the film (that fans have spotted so far, anyway), most blatantly when Lorraine Warren (Vera Farmiga) is sat reading in her home, and his name appears on the bookshelf, spelled out by five large letter blocks.
These Easter eggs only enhance the pervasive creepiness of the year's most terrifying horror movie villain, and add to the film's rewatchability as you keep your eyes peeled for more nods to the paranormal baddie.