The Great Roly-Poly Pox Pandemic
It's a little-known fact that the ancient world was once threatened by a giant, mutated roly-poly bug that rolled its way across the land, leaving a trail of destroyed cities and confused archaeologists in its wake.
Caused by: Mysterious Ancient Bug, Overly Complex Antivenoms
The Great Flood of the Fuzzy Mammoths
When the skies grew too full of fluffy, yet somehow terrifying, mammoths, the earth decided to just give in and flood the whole continent to get rid of them.
Caused by: Fuzzy Mammoths and Excessive Hair, Overly Fluffy Flood Control Systems