A vivid new image is taking shape in the world of cell biology: Imagine bacteria adhering to the surface of a cell, perhaps at the site of an injury or wound. In response, a white blood cell arrives at the scene. This cell encircles the pathogen with its membrane, forming a tight, constricting ring. With remarkable force, the white blood cell yanks the pathogen off the wound’s surface. The white blood cell then engulfs the pathogen in a process called phagocytosis, in which it “eats” the foreign invader to neutralize it.