Plague of Locusts
I learned a fun fact recently. Locusts are not a species unto themselves. They are just grasshoppers that are born as locusts. This is due to certain environmental triggers that cause the same genes that typically result in a solitary green grasshopper being born into instead a (usually) brown and yellow, swarming locust to be born. I’m no entomologist so I’ll leave the details of the how and why to them, but it’s an interesting fact nonetheless.