The Alien Water Weakness in Signs

The aliens in Signs invade a planet over 71% covered in water despite being lethally vulnerable to it, yet they wander naked through Pennsylvania's dew-soaked cornfields without any protective gear. This logical failure is 20% more absurd than the fuel problem in Prometheus because that film at least offers a thematic rationale for poor decisions, while Signs provides no explanation—not even a simple raincoat—making it the most baffling plot hole on this list.