"Unnatural pests"
From the Adventure journal of Alexander, the halfling.
As we crept into the dungeon, Lundiel warned me that my expertise would be required to deal with the many creatures of nature found within. If only that were true. As it turned out, none of us were prepared to handle the unnatural forces we encountered.
If only I had listened to my instincts! I should have known there was something wrong the instant we reached the bottom of the crudely carved steps and were hit with the unmistakable stench of death. In my foolish overconfidence I failed to recognize that whatever was in this cave would not be within the range of my knowledge - for the vermin that we found were not of nature!

Spiraling into those evil depths, we turned from the stairs to face enormous rats, larger even than the largest dog. They immediately swarmed us, viciously pushing forward, overpowering us with mindless intensity. Chattering in a low and distorted tone, the creatures surged forward, craving living flesh.
As if the horrible stench were not enough, the very appearance of these beasts was nauseating. It was clear that we were facing true abominations in those rank depths. The rats were truly hideous - skin and fur in extreme decay, with many missing eyes, likely eaten in hungry attacks by their fellows.
These weren
t normal rats: they were undead!