Plague of Locusts

Behold, the locust.

Alone? A simple and usually solitary short-horned grasshopper.

But when the conditions are right?

Well, first let's discuss what those conditions are. Following a phase of drought and rapid vegetation growth, locusts begin to breed rapidly, with the groups of nymphs developing into wandering swarms of winged adults - and it is in both forms that they become a Plague of Locusts.

During "swarming" behavior, both nymph and adult populations are known to cause serious damage to crops and fields by stripping them thoroughly. Adult locusts in particular are powerful fliers capable of traveling great distances - not only is the phenomenon unsurprisingly widespread, it's also Older Than Dirt, dating back to the ancient Egyptians and prehistory in general. The devastation of crops are a major factor in famines and human migrations, to the point that locusts themselves are considered harbingers, if not carriers, of actual plagues.

Funnily enough, locusts themselves have been used as a source of food, with many cultures across Africa, West Asia and East Asia considering locust a delicacy. The Bible itself mentions "bald locusts" being acceptable for the Israelites as far back as the Book of Leviticus 11:22; in the New Testament, Matthew 3:4 and and Mark 1:6 assert that John the Baptist ate locusts and wild honey during his stay in the wilderness.

In fiction and literature, the connection between locusts and plague has led to them being portrayed or symbolized as Walking Wastelands, often to the point of being inherently poisonous themselves.