"Lampreys are an ancient extant lineage of jawless fish of the order Petromyzontiformes, placed in the superclass Cyclostomata. The adult lamprey may be characterized by a toothed, funnel-like sucking mouth"

In order to survive in a dimly lit world these parasites have evolved large eyes to see their prey, the large and gargantuan sea beasts that inhabit the dark, dim, ocean.