By Bradley Jolly A horror film based on the pitiful Willy Wonka Chocolate Experience event \- and star its creepy character “The Unknown” – is set to be made. The movie with the same name will be about an illustrator and his wife, haunted by the tragic death of their son, escape for the remote Scottish Highlands – where an “unknowable evil awaits them.” It is thought this will occur in the form of the character, seen at the Willy Wonka event wearing a silver mask. Parents had no idea how the scary character was linked to Roald Dahl’s book and, in one video taken at the event, a ghoul jumps out…