Death Roll

The material below is Open Game Content from a 3PP Source

Death Roll (Ex): An eidolon can spin its head or whole body repeatedly as a swift action after grappling a foe of its size or smaller with a bite attack. The eidolon makes a CMB check, with success allowing it to inflict its bite damage, knock the target prone, and maintain its grapple. An eidolon must have the bite evolution to select this evolution.