It is a from a character in Frank Zappa's songs. I was called that in my Air Force days. Better known as the Mudshark in your mythology (dum dum dum).
You are the first to ask.
Well right about that time peoples,a fur trapper, who was strictly from commercials.........jumped up from behind my iglo....... & said peekaboo,woo oo oooo & went right upside the head of my favorite baby seal.........with a lead filled snow shoe
Anyhow there is much more to the mudshark,it goes way back when Flo & Eddie were still with the Mothers of Invention,they used to do a live routine called the Mudshark & Bwannadick,funny stuff but way too filthy to repeat,it's on the Fillmore East album.
Flo & Eddie went on to form the Turtles after leaving the Mothers of Invention.