Bizarre, Prehistoric Ratfish Chomped Prey with Buzzsaw Jaws
...
If Helicoprion bit one of the coil-shelled ammonoids or nautiloids just right, this same process would have automatically shelled the cephalopod. In the case of a head-on bite, Ramsay and coauthors write, the back teeth of Helicoprion could have gripped the cephalopod's body while the front teeth pushed the shell out of the mouth. The overall effect, Ramsay and colleagues propose, "may have formed a novel mollusk shucking system." Helicoprion - it slices, it dices, and makes Julienne ammonoids.