10 More Glaring Plot Holes You Didn't Realise The Movie Actually Solved

Typically, when you go into any movie written and directed by M. Night Shyamalan you can expect there will be a big twist before the credits roll. In The Sixth Sense, it was that Bruce Willis had been dead the whole time, in Unbreakable, it was that Samuel L. Jackson's Mr. Glass was behind everything, and in Signs, it was that the invading aliens were allergic to water.

This has been called out as a plot hole by many, who say that if the aliens were so vulnerable to as little as a drop of H2O, why did they invade a planet 70% of which was comprised of the stuff?

There is a popular fan theory that suggests the aliens weren't in fact aliens but demons, and that they were reacting to holy water. However, you don't have to look to fan theories when the answer is categorically presented within the confines of the movie already.

There is an easily missed line where someone on the radio claims that Earth is actually experiencing a raid rather than an invasion. It may sound like splitting hairs, but there is a distinction that makes a big difference. With it being a raid, the aliens didn't come for the planet or to stay for long, as they would have with an invasion. Instead, as Earth would be the only place to find a nice healthy crop of humans, they were looking to abduct and move on with minimal water contact.