I don’t see that you included them in your list. “Terror” something sounds more frightening than “dire”, to my mind anyway.
Sorry – my memory played me false there.
Of course, in D&D, darned near every animal has a dire version.
It’s right there in the name: Dire and direr. Right? 
I’m pretty sure I dated one in the 90s. She was both straight and, as it turns out, pretty dire. Lessons learned from that one.
Sounds like an updating of the attempt to recreate the aurochs during the period before World War II by the Heck brothers.
I want a dire sloth
“It’s a Dire Sloth! Walk for your lives!!”
Their claws are rather huge and certainly dangerous when backed by multiple tons, but yeah their top speed is estimated to be about 5 mph. We do have DNA for them, so it’s possible to play genetic games with it.
It’s thought that plants like avocados evolved their big seeds to survive their digestion.
Interestingly, the species was scientifically described in 1796; that’s how the species has the simple name “big beast”.
The Megatherium shows up as the Really Dangerous Creature in the 1948 movie Unknown Island (which also features some very unconvincing T. rexes that look like people in T. Rex costumes, much like the ones sold today). The Giant Ground Sloth actually looks and cts more like a misshapen ape than a Giant Ground Sloth, but at least they get points for trying something new.
We actually have specimens of Megatherium hide, which has a gazillion tiny bony nodules embedded in it, making it like a coat of stony mail.
There’s a sample of this on display at the American Museum of Natural Hstory in New York.
Yep. My personal favorite of extinct mammals is the dire armadillo, commonly called the glyptodont. Sloths, armadillos, and anteaters are related and have bony hides to greater or lesser extent. Glyptodonts take it too the extreme.
They could get as large as two tons. Not something to mess around with.
Honestly, that might lead to a few deaths, but no Cenozoic mammal is much more dangerous than the polar or kodiak bear or the tiger. Sure the short face bear was somewhat larger, but the Smilodon is only slightly larger than a tiger.
It would be an animal “not to be messed with” but not otherwise dangerous.
I once got a DM to promise to add in a dire snail. But the game ended too soon. I still miss the possibilities.
I dunno – a Polar Bear or a Tiger seems pretty dangerous to me. And even if it wasn’t angry, I would think you could get a lot of collateral damage from a Paraceratherium (formerly the Baluchitherium. I don’t know if the name change makes it more angry or not), even if it wasn’t mad at you.
As for Unknown Island’s Giant Ground Sloth, as I mentioned, it acted and looked more like a mutant giant ape. Don’t rely on movie makers (or thriller novelists) to stick t strict accuracy when the plot is on the line.
They certainly are- But there are less than a hundred tiger attack deaths and injuries most years and the same for bears. However, even if a whole zoo worth of “lions and tigers and bears” (oh my), got loose, the casualties would be that bad- even dinos wouldnt cause the devastation that Jurassic park showed.