This is massively cool. There is so very little that cannot be imagined that has not been tried, even if unsuccessfully or not for very long, by the forces of random mutation assisted by natural selection and a soupcon of luck.
Remember how the aliens in, um, Alien(s etc.) had two jaws, and the big one which could take your head off would open and a small one capable of biting your nose off would come off purely, it would seem, to terrify people even more before killing them. Maybe stressed meat tastes nicer.
Nope, that wasn't a new idea either.
Moray eels do it too. (Courier Mail)
Yay! Go evolution!