Deep is a very small humanoid fish baby with blue-green scales, fin-ears, a mop of messy black hair, an angler bulb, three arms, three blue eyes, and a whale tail lower body with no legs. Sebastian is the father and mother of it, looking exactly like the baby but much bigger, sassier, meaner, and with clothing. He is highly protective of Deep, and will kill anyone who hurts or upsets him without hesitation. If Deep likes someone, he might be more soft towards them.