Real Life can be much more interesting than fiction. Some real life events sound like the first 10 minutes of horror films...
Prehistoric killer from the ocean's depths. A shark rarely seen because it exists in deep waters of the Atlantic and Pacific Ocean... and relativelu shallow waters around Japan that is often called a "living fossil" because he retains features from as far back as the Jurassic era.
Of course, it's not a danger to humans because of the depths it lives at and the fact that it's so rarely encountered alive.
Except, it's beginning to seem around Japan and possibly other areas. But although science was a little wrong about that, it's right about the fact that this eel-looking creature which is presumed to attack like a snake doesn't eat humans.
Because they're right about that, if not the depths it can live at. But they do know it only grows to 2 meters max. Because we know so much about this rarely encountered creature that lives in the unexplored ocean depths.
And if there's one this horror movies have taught us it's that animals are never bigger then they're meant to be.