Nacht und Nebel
Nacht und Nebel ("Night and Fog") was a directive () of Adolf Hitler on 7 December 1941 that was originally intended to remove all political activists and resistance 'helpers', "anyone endangering German security" ("die deutsche Sicherheit gefährden") throughout Nazi Germany's occupied territories. The name was a direct reference to a magic spell involving the "Tarnhelm" ("stealth helmet") from Wagner's "Rheingold". The Tarnhelm could make its wearer invisible and instantly transport him to another location.