UFO/UAP
I suppose I can’t think of anything scarier than being in charge of a weapon and losing control over said weapon. Imagine being on duty at a nuclear silo, and it’s your job to maintain the integrity of systems and operations. A UFO hovers over you and activates those system, giving the all clear’ for launch, activating the countdown. You can’t turn it off. You can’t unplug it. You might say to yourself, this is a nightmare. This can’t happen.
It happened. More than once.