Space Nazis are a common theme in sci-fi and fantasy dealing with the aftermath of World War II or the evils of the third reich when it was in its prime - the genre is also based on actual conspiracy and fringe scientists that believe Nazi Germany had contact with aliens and may of even evaded justice via the use of advanced technologies (widely ridiculed with the "Nazis on the moon" subtype of this genre).
The usual theme is of surviving Nazis (or their descendents) living in or colonizing space - yet still retaining their loyalty to the third reich and Hitler's ideals, variants can also deal with alien or exotic weapons being in the hands of the actual third reich during their power (or in alternate time-lines where the wars are either still being waged or the Nazis succeeded in their conquest).
A popular idea is that the Nazis still manipulate events by having retreated to Antarctica after World War Two and thus the Roswell UFO crash was really a downed Nazi spaceship and the bodies of aliens were war prisoners. The fleets of UFOs seen by humans since World War Two are said to be amassing armies of "space Nazis" driven on a new Nazi regime.
The term can also be used (sometimes negatively) for alien / fantastical races in fiction that are clearly inspired by the Nazis.
Examples In Fiction
- The Rebels from FTL: Faster Than Light can be considered Space Nazis due to their similar beliefs in a "master race" and human supremacy.
- Melakon and the Ekosian SS from Star Trek were literal humanlike aliens who modelled their society after the Third Reich due to the actions of a misguided Federation official who believed Nazism could benefit society if its xenophobic elements were removed.
Live Action Films
Anime / Manga
- Nazi UFOs (a conspiracy / alternate history theory that Nazis had access to alien technology or were even in an alliance with an alien race (the mythical Aryans) )
- Imperium of Man (a morally dubious faction from Warhammer 40,000 that has elements of medieval Catholicism (specifically the witch-hunting elements) but policies that are more in line with Nazism, such as an official doctrine of absolute xenophobia)