It's now such a well-worn formula that it's hard to remember the impact The Blair Witch Project had on release back in 1999. Directors Eduardo Sánchez and Daniel Myrick fooled the world into thinking they had unearthed genuine material, opening with the ominous title card: 'In October of 1994, three student filmmakers disappeared in the woods near Burkittsville, Maryland while shooting a documentary. A year later their footage was found.'

'That's why the whole genre is called "found footage". We didn't even name it, we always referred to it as "first person cinema",' explains Sánchez with a wry chuckle. 'To us it was a gimmick. It worked because the story of the movie drove the technique, the idea of these people getting lost making a documentary, so there was a clear vision of how we wanted that to look.'

Blair Witch became one of the most influential horror films of the modern age and is the subject of a new feature length documentary, The Woods, which had its world premiere at Glasgow's FrightFest. 'The footage had been sitting around our offices since Blair Witch,' says Sánchez. 'Last year it was the 15th anniversary and we thought it was time to get this footage out there. I think certain fans will really dig it because it really was a unique story. So Russ Gomm went out and edited it, he's done a really good job. It's a fun film, seeing me and my partners 15 years ago is a trip.'

Sanchez continued to work in the horror genre. 2011's Lovely Molly, an unnerving, insidiously spooky, twisted ghost story starring Gretchen Lodge, being a particular high point in his career. 'It's probably my best film to date,' adds Sánchez. 'There was just something about it that you can't quantify. The same thing happened with Blair Witch, a certain amount of luck, serendipity and the planets aligning. Lovely Molly was one of those things that just blossomed out of this very dark idea and took on a life of its own.'

Recently making a move into television directing episodes of From Dusk Till Dawn and BBC's creepfest Intruders, he's finally returned to the format he brought to the masses with Exists a wickedly entertaining sasquatchploitation movie. 'Exists actually started as a conventional film but we realised it might be time to go back to found footage. When I analysed the idea of bigfoot I realised bigfoot is a found footage creature, whenever you see bigfoot it's found footage.'

Exists is available on DVD (Entrainment One) from Mon 6 Apr.

EXISTS Trailer (2014)