Zombie worms (Osedax roseus) eat away at the bones of a dead whale that has fallen to the seafloor in Sagami Bay, Japan. These bizarre worms rely on whale bones for energy and are what scientists call “sexually dimorphic”—the male and female forms are markedly different. In this case, the males are microscopic and live inside the bodies of the female worms! This allows females to produce many, many eggs to disperse across the seafloor. Few of these will land close enough to sunken bones to survive.