Identification of landmarks, including the diaphragm and lung, is very important as the initial step in pleural ultrasound.4 It is important to note, and may be under-recognized, that acute free-flowing blood in the pleural space appears anechoic. Next, the “hematocrit sign” may appear, which represents a separation of erythrocytes from the plasma as they settle in the most dependent portion of the pleural space. With time, clotted blood may appear; it is hyperechoic,5 appearing somewhat like a jellyfish (Fig 2, Video 1). Fibrin strands can be present after enough time has elapsed for the blood to coagulate. All of these signs were present together in this case (Fig 2).