Welcome to a vibrant social scene that has operated largely in secret until the past few years. Its participants don't seem to mind going unnoticed. They congregate in immense numbers to fend off enemies and the brute forces of nature, to obtain food, to reproduce, and to move to greener pastures. They're adept at forming bands to hunt prey, which are consumed on the spot. Vital messages repeatedly course through these assembled throngs. Under some circumstances, certain community members sacrifice their lives for the good of the rest. At other times, entire congregations cozy up to unsuspecting hosts before coalescing into stone-cold killers.
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