Your arms morph into flippers. Your back grows round and hardens. You swim through thick ocean waters, dodging fishing gear and ships that can maim along the way. You are a loggerhead sea turtle—or at least that is what your brain perceives when you wear a virtual reality headset and enter Project SHELL (Simulating Living Habitat Experiences of Living Loggerheads), a research project of the University of Oregon and the University of Florida.