Not evil spirits who want to possess mages! But rather, bad meat!
In London, butchers who sold meat that was “putrid and stinking, an abomination to mankind;” “putrid, rotten, stinking, and abominable to the human race;” and “putrid and corrupt, unwholesome as food for man, and an abomination” were “without exception punished… by being placed in the pillory and having the putrid matter burnt beneath.”
Dragon Age abominations really do look rather like bad meat, too.
Kirkwall Was Totally Built On a Hellmouth 