Giant Silverfish

It's uncommon for silverfish to congregate in sufficient numbers to constitute a swarm, but forgotten libraries or similar out-of-the-way places might harbor a multitude of the voracious pests.

A common pest with a silvery carapace and an undulating, fishlike scuttle, the nocturnal silverfish infests homes and libraries throughout Golarion. These insects aren't typically dangerous, but their tendency to devour books and clothing often puts them at odds with larger creatures.