The Unmistakable Plot Hole In M. Night Shyamalan's Signs

Even M. Night Shyamalan would have to agree his career has been more hit-and-miss than most. But even as Shyamalan's career has seen as many unexpected twists and turns as, well, one of his own movies, the early 2000s found the writer-director on top of the world following the release of his iconic 1999 supernatural drama "The Sixth Sense," and its beloved superhero follow-up "Unbreakable," which arrived just a year later. Based on the success of those two films alone, Shyamalan essentially had the license to make whatever movie he wanted next.   

The movie he made was 2002's sci-fi thriller "Signs," which found Mel Gibson portraying a faith-challenged priest whose family and land are beset upon by invading aliens. Co-starring Joaquin Phoenix, Rory Culkin, and Abigail Breslin, the slow-burning "Signs" hit theaters at the height of the '02 summer movie season to largely positive critical notes (per Rotten Tomatoes), and went on to earn a whopping $408 million in worldwide ticket sales (per Box Office Mojo). Almost a decade later, "Signs" remains one of Shyamalan's most popular films, with many continuing to praise its tautly-wound narrative, and the director's beyond-clever take on the alien invasion genre. Still, even the most ardent fans of "Signs" might agree the film's final, alien-defeating plot twist might actually be more of a glaring plot hole.

Some of the harsher critics of "Signs" might even say that said twist — in which it's discovered the big bad aliens have a deadly reaction to water — sinks an otherwise excellent thriller. Whether you love "Signs" or not, it's easy to see where those critics are coming from as the film is more or less about Earth being invaded by an advanced alien race capable of interplanetary travel.

That obviously puts them light years ahead of humanity in terms of technology. It stands to reason that such an advanced race of beings would likely be aware that even a little bit of H2O could be their undoing. And assuming that's the case, it makes absolutely no sense that they'd want anything to do with a planet whose surface is about 71% water, let alone have interest in invading said planet in a hostile takeover. Even more problematic is that they apparently showed up on Earth without a single weapon (save for that sleep-inducing spray) to either attack or defend themselves from weapon-loving Earthlings — which is a plot hole in its own right.

The flip side to the water argument is that it's entirely possible the invading aliens had never come across it in their travels, and simply had no idea it killed them. Water has, after all, proven exceedingly scarce in our own solar system, and is presumably just as scarce in the cosmos at large. Whatever the case, the infamous water twist remains a glaring plot hole in the otherwise fantastic "Signs."