The Elasmotherium existed as many as 29,000 years ago (here on Earth, even though it certainly doesn't look native to our planet!).
Their massive horns require huge muscles in their back, as you can see from the hump jutting out. Taking a look at their skeleton also shows support in the form of bones:
Here's a size comparison chart as well (but unfortunately doesn't show the horn), with humans in the bottom left for size reference:
You can read more about this "thin plate beast" on Wikipedia:
Saw this on reddit and thought it was way too cool/inspiring not to share.
