Wikipedia
A Seilbombe (, plural Seilbomben, ), literally "rope bomb", was a secret German weapon developed during the Second World War designed to disable the electrical power grid of an invaded territory. Equipped with it, a German Messerschmitt Bf 110 fighter plane or an Arado 196 float plane would fly low at night over areas near enemy power plants or urban centers where power lines were located and would use it to cause local blackouts. This would, it was hoped, lead to civilian panic and the inability of local opposing forces to coordinate a defense. The piloting of planes so equipped was extremely dangerous, as it required the pilot to fly his plane almost directly at enemy power lines in the dark when visibility was already severely limited and within easy range of anti-aircraft fire.