What prehistoric animal (s) would you be the most afraid of?

TomGarand
(Inspired by @NorthwestRider!)

It seems like when humans just existed, and even before then, the Earth was filled with nightmare fuel. Apart from having the Keanu Reeves of dinosaurs (Tyrannosaurus Rex), our planet also had dire wolves, Megalodon, saber-toothed cats, and worse.

So in this question, I am asking you all, what prehistoric animals would you be the most afraid of if they were still alive, and why? I'll go first.

1. Terror Birds. A family of carnivorous flightless birds that lived in the USA after the dinosaurs got Thanos-snapped. These things are terrifying because they are basically death ostriches. Not only could they run at speeds of around 40 miles per hour, but these apex predators also had bone-shattering kicks, and could kill their prey by slamming their heavy, sharp beaks into them like bony axes. And to make matters worse, some species of terror birds like the Gastornis or Kelenken could grow to be 6'7 or 10 feet tall.
What prehistoric animal (s) would you be the most afraid of?
2. Quetzalcoatlus. I'm so glad this thing is not alive anymore. First off, this was the largest flying animal to ever live and weighed 550 pounds. When standing up, they were as tall as modern-day giraffes. Imagine that thing looking down at you! It'd probably be worse seeing them fly, because they had a 36-foot wingspan, and could reach speeds of 56-80 miles per hour. Also, it's been hypothesized that they ate small animals like baby dinosaurs, so they probably could eat humans if we coexisted.
What prehistoric animal (s) would you be the most afraid of?
3. Utahraptor. Remember those Velociraptors from Jurassic Park? Now make them 6'5, 23 feet long, and 1,100 pounds. Oh, and give them the potential to hunt in packs like their much smaller cousin. Yikes.
What prehistoric animal (s) would you be the most afraid of?
So what prehistoric animal (s) would scare you the most, and why?
Updates
+1 y
Also, one more thing. The animals you'd be afraid of DON'T have to be any of the ones I listed. These are just the ones I would personally fear the most.
What prehistoric animal (s) would you be the most afraid of?
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