These critters are very curious and friendly. They mostly feed on the magic in the water they live in, and will die without a steady magic diet.
Sucker sharks' bodies will change to reflect the magic they consume. Their bodies are extremely susceptible to the effects of magic, making them a favorite among magicians.
Sucker sharks are often used by researchers to tell exactly how much and what kind of magic is in an area. New ones are bred for quickest turn time.