Unknown of the Deep
Why are we, homo sapiens afraid of the deep dark blue? Or the unknown that dwells within the vast emptiness? Should we dive into its depths, are we prepared to face the inevitable that awaits us? It's not thalassophobia that we're afraid of, but what we are not prepared to face. Human minds, just as the ocean, is divided within 3 layers, the consciousness, sub consciousness, and unconsciousness.
Deep within our unconscious mind lays our fears, irrationality, pain and traumatic experiences. Characters, moments, and emotions that we would never have acknowledged breathes life there, and this creature as seen is an archetype of all that is undesirable.
A lesson to note is to reconcile those fears and traumatic experiences, what brings us anxiety, is teaching us not to exorcise, but recognize the demons that dwells within.