3. How Do The Aliens Deal With Humidity? - Signs (2002)
Signs, M. Night Shyamalan's third film, is generally one of his better efforts, and that's down to some great performances (Mel Gibson and Joaquin Phoenix are both excellent) and some generally terrifying sequences. On its most basic level, though,
Signs encompasses a relatively run of the mill alien invasion story, one which apparently takes its cues (in its ending, at least) from H.G. Wells'
War of the Worlds. In
War of the Worlds, it conspires that the aliens - who, for a time, are successfully defeating human forces - didn't anticipate that the germs on earth - germs that we, as a human race, have been evolving to fend off for millions of years - could kill them. Whoops. In
Signs, it's water, though Shyamalan seems to have neglected two things: firstly, there's constantly going to be water vapor in the air, so they likely wouldn't have been able to movie about in our atmosphere. Secondly, why invade a planet that is 71% water? Surely they're advanced enough to realise
that?