Bobbing along on the research vessel Western Flyer just outside California’s Monterey Bay, marine biologist Karen Osborn and her colleagues were hauling deep-sea fish to the surface for cataloging and a photo shoot. Osborn got her hands on a fangtooth, a self-explanatory creature with a mouth full of nasty, big, pointy teeth, attached to a stout, teardrop-shaped body. Using her custom-built...