7. Signs (2002) – The Aliens Are Actually Demons
Another theory that has received widespread attention posits that the aliens in M. Night Shyamalan’s Signs are actually demons – and what makes this theory great is how utterly ridiculous it sounds until you start considering the evidence that backs it up.
In the film’s climactic scenes, Signs‘ aliens are undone by their aversion to water, which makes their decision to invade a planet composed almost entirely of water a little nonsensical. This theory actually fixes the well-known plot hole, and is backed up by various scraps of evidence that appear throughout the film.
Mel Gibson’s protagonist, Graham Hess, is a former preacher who is disconnected from his faith after the death of his wife. The theory that Signs‘ aliens are actually demons mostly stems from this – and it perfectly explains their aversion to water.
The particular plot point is learned by the Hess family when the aliens come into contact with a glass of water left out by Graham’s daughter Bo. The theory posits that this water is actually holy water, and that’s why the aliens demons are weakened (and ultimately defeated) by it.
The theory is also backed up by numerous biblical references throughout the film. It’s yet to be confirmed whether or not it was what Shyamalan actually intended for Signs, so at present, it remains an interesting (and remarkably convincing) theory.