Guitarfish are really rays, not sharks, but they're closely related and some species are also called sand sharks, so thought this one could slide as a "Shark Week" parasite. Besides, the irony of this parasite is just too much to pass up. Branchotenthes robinoverstreeti is a recently discovered monogenean parasite that infects the gills of guitarfish in the Indian ocean. The haptors of B. robinoverstreeti, which are the posterior structures used to attach to their hosts, look strikingly like the head of a guitar with the six tuning keys. The parasite was named after Dr. Robin Overstreet, an eminent parasitologist of the Gulf Coast Marine Laboratory.
Image is from the original paper.