This creature resembles an ordinary shark from tail to mouth, but the unusual shape of its lower jaw marks it as something else. A whorl of teeth spirals inward, tiny at the center, but long and brutal farther out.
Helicoprion Shark CR 6
When a helicoprion hits a Medium or smaller creature with its bite it can, as a free action, attempt to grapple and then pin that creature should the initial grapple be successful. Once the target is pinned, the helicoprion continues to do its bite damage (including bleed) for as long as it maintains the pin.
Environment temperate oceans
Organization solitary, pair, school (3–5)
The helicoprion is a bizarre beast to behold. The remarkable physiology of its mouth allows it to flick out its bottom jaw, unrolling the whorl of teeth and snaring prey along its length. As its powerful muscles roll its jaw, the prey becomes trapped in a spiral of ragged, brutal incisors. Once it has captured a hearty meal, the helicoprion retreats in a thickening cloud of its victim’s blood to patiently await the slowing of struggles and the imminent demise of its dinner.
Pathfinder Adventure Path #57: Tempest Rising © 2012, Paizo Publishing, LLC; Author: Matthew Goodall.