The owl represents the good in Clay. The hope and love. It only makes a few appearances(just like the good in Clay). On the other hand though is the cat, which is in the story from the very beginning. Representing the hate, sadness and anger in Clay. He has a mental condition called delusional disorder. Which I checked does also cause hallucinations. Which aren't as bad in the beginning even though he doesn't have meds. But his mind is just destroyed in the end so he ends up having some trippy hallucinations.