These weird things hang around in the lagoon. Why they are called guitarfish is kind of evident, at least with a little imagination. Although this individual was quite slim.
Guitarfishes are rays, and thus related to manta rays and stingrays. Except for that their tail half looks like it belongs to a shark, with two dorsal fins and a vertical tail fin. Just a lot more friendly-looking. I nudged one with my toes and it did not seem to mind me at all.
These guys and girls have as a species been around for some 100 million years. Thus a lot longer than a guitar, or even a banjo. And certainly longer than us humans.
(Walvis Bay, Namibia; July 2017)