Some of the truest and most alien horrors the Ruin inflicts are those that subvert human understanding of the world around them. The chimera are bizarre and grotesque amalgams of various mundane people and animals (and perhaps more...) into forms that combine and agglomerate familiar creatures into monstrosities both tragic and cruel — and immensely dangerous.
The transformation of a person or beast into a chimera happens over an extended amount of time, depending on the potency of the Ruin at work. Every individual chimera is its own creature the Ruin has befouled in the vicinity and called into mutual presence.