
It is humid, the air heavy and still, growing thicker as beach turns to marsh. Insects float lazily over the water, and you swat the occasional mosquito away from your face. You are suddenly aware of how quiet it is, no birds chirping or animals rustling in the grasses, and the feeling registers too late. Something is watching you.
You scan the treeline, looking for motion and signs of movement in the foliage. Nothing. You look again, and realize your mistake. You were looking for something predator sized, maybe a wolf or a bear. What’s watching you is a monster, taller than you are at the shoulder, its head easily twice the size of a bear. And then it lowers its massive head and charges.
Get ready to fight this giant, prehistoric dork: Andrewsarchus.
Andrewsarchus is still largely a mystery. Only one skull has been found, and there’s a lot of debate over how this creature fits into the mammalian family tree, what it ate, and how it looked. When its skull was unearthed in the 1920s, paleontologists described it as an apex predator and named it the largest to ever live on land, estimating that it stood six feet tall at the shoulder and measured about twelve feet long. Comparisons were drawn to wolves, though Andrewsarchus predates wolves by millions of years.
Today, it is widely accepted that this giant ungulate is more closely related to whales and hippos. Modern paleontologists also believe Andrewsarchus was not a predator but an omnivore, with a diet closer to that of modern pigs than wolves.
Don’t think you’re off the hook because this big bastard may not have been an active predator, though. If its modern day cousin gives any clues to its behavior, it’s actually much worse to run into Andrewsarchus than a giant wolf or bear. Hippos are infamous for their aggression, killing and maiming more humans per year than any African predator. The combination of their size and teeth make hippo encounters fatal, and lucky you, Andrewsarchus is bigger and toothier than their modern kin.
Another horrifying aspect to consider is that its closest relatives, whales and hippos, are both social creatures, traveling in pods or, if you’re a hippo, bloats rather than solo. So if you run into one Andrewsarchus, you may actually have to deal with a whole angry family.
So, what do you do when there’s about 2,000 pounds of angry prehistoric land whale bearing down on you?
First of all, don’t let the size fool you. Odds are good that Andrewsarchus will be able to outrun you. Hippos are much faster than humans on land, running as fast as 30mph, so don’t bank on being fast enough to get away. You can try serpentining, its bulk could make quick maneuvering difficult, but I sure wouldn’t want to bank my life on being able to zig zag away. You’ll probably want to get out of open space as fast as possible. Any obstacles you can put between you and this megafauna will help buy you time, so head toward trees and rocks. You could try running for water, but since this megafauna is related to both hippos and whales, it’s probably faster than you in water, too.
If you have no choice but to fight Andrewsarchus, know that this thing is bound to be very strong and very tough. You’ll need a lot of arrows and crossbow bolts to down this guy, possibly more than you could even carry. Hopefully you’re traveling with some tough friends who can help. This might be time for your druid to finally shine, assuming they’re adept at befriending animals. Or, if you have some magic users who are good with weather, you can kill it off the same way nature did: by slowly changing the climate of its home in modern-day Mongolia from a warm, nearly tropical coast to a cool and arid desert. All you have to do is raise the Himalayas and wait a few million years.

Dex Dylan is the founder and acting president of the International Society of Astrocryptozoology. For decades, Dex has scoured the skies and seas (and sometimes the land, but honestly it’s so crowded) for hints of unusual life forms, and has done extensive research into the possible existence of chupacabras on Mars.