> I always imagined some twisted diminutive demonic swarm of insects

Behavioral ecologist Stephen Simpson has proposed the cannibalistic forced march hypothesis[36], that is, the forward motion of a locust swarm is essentially sustained by each individual’s imperative to avoid being eaten by the locust behind it: 1) Align their body axis with neighbors (parallel) to minimize the chances of a side-on attack and present their narrowest possible profile to the individual behind. 2) March forward to bite and feed on the abdomen of the locust immediately ahead.

A billion crazed insects marching through eating all your crops while cannibalizing each other does seem relatively twisted and demonic.