I want to shine some more ligth on Echo. Myke-4 Astor teams up with the Adult Legion of Super-Villains (for unknown reasons) calling himself "Echo". While the LSV try to lead their heroic counterparts to their deaths, Echo ambushed Cosmic Boy. Using his sound manipulation (manifested as vibration waves and sonic scream), he nearly defeated Cosmic Man (that time line's older Cosmic Boy)! But Cosmic Man use his magnetic control to take away the air from Echo (since it's oxygen and nitrogen are slightly paramagnetic) to knock him out and render him powerless (since sound travels through air).