Jurassic Park nothing. The most terrifying dinosaurs are the ones that walk among us today, in real life.
In light of recent events, we feel it necessary to remind the public that dinosaurs still exist and that, yes, feathers can be scary:
The Great Tit seems like a gentle enough bird, that is until you learn that its nickname, "The Zombie Tit," refers to its proclivity for seeking out hibernating bats, crushing their heads AND EATING THEIR BRAINS. [Warning: Link features bird and bat demise]
The Harpy Eagle has the largest talons of any eagle on Earth. It's also got four of them on each foot. That makes the single-sickled feet of JP's raptors look like safety scissors.
For the uninitiated, the cassowary is a behemoth of the bird world (second-heaviest, behind the ostrich) with a face perpetually frozen in an expression resembling that of a frat bro who just challenged you to a bar fight. They can grow to over six and a half feet tall, weigh well over 100 pounds, and gallop around at speeds of over thirty miles per hour – an impressive biomechanical feat for a creature with legs that might best be described as "death-cudgels with knives attached." Seriously, look at this thing. You see its feet? The middle toe on each one features a dagger-like claw that can grow up to five-inches long.*
If you've ever wondered what it looks like to stare murder in the face, try looking into the face of a great blue heron as it stalks, snatches, and swallows a gopher. Even as the gopher wriggles visibly in the heron's esophagus, the bird's gaze is ice. Freaking. Cold. Trifle not with the great blue heron. [Warning: Link features graphic gopher-wriggling-in-neck footage]
*NB: Cassowaries are actually notoriously shy creatures (it's the ones habituated to human contact that are dangerous), but that doesn't make them any less deserving of your respect.