Little red jellies are commonplace near the deep seafloor in Monterey Bay and around the world. Most of them are small—less than five centimeters (two inches) across—and a ruddy red color, but we know little else about them. Though MBARI researchers have observed them for decades, their role in the food web, what they eat, and what eats them, still largely remain mysteries. Now scientists are finding that even their evolution and relationships to one another are probably incorrect.