In science-fiction seemingly religious concepts, objects, processes, or events having a basis in extraterrestrial origin is a recurring narrative tool. As science-fiction is typically more interested in scientific groundings for phenomena as opposed to supernatural ones, more often than not those who believe that inexplicable phenomena is divine are incorrect, and commonly those who believe it is alien in nature are correct. A common science-fiction trope is religions being built on the false belief that alien technologies are in fact religious artefacts or that an alien species is in fact divine. The beliefs are usually born out of the concept that highly advanced or very unusual technologies or capabilities may appear like those of gods, and that religion provides easy-to-understand and intuitive explanations of what unknown technologies, powers, or species actually are. In many stories the mistaken belief that the alien phenomena is divine has negative or even existentially-threatening consequences.
A classic example of this concept is that of The Forerunner in Halo. The Forerunner are an ancient alien civilization that were key in the history of humanity and who built many technologies and cultivated many worlds. Among them was the Halo array which was built to eradicate all life in the Milky Way. The Covenant are an alien religion in the games that mistakenly believe that The Forerunner were gods, that their technologies are holy artefacts, and that activating the Halo array will lead them on the "Great Journey" to the afterlife. Similarly, in Dead Space the religion of Unitology is formed around the belief that the artefacts known as Markers are alien in origin but will provide passage to the afterlife. In reality the belief is largely the result of hallucinations the Markers cause in intelligent organisms nearby and ultimately the Markers convert people into the destructive alien Necromorphs.
In Assassin's Creed the First Civilization were an alien species that preceded and created humanity and communicate with humanity throughout history in an attempt to protect them. With religious belief being so historically common they are frequently viewed as gods. In Mass Effect there exists a species of half-machine half-organic creatures called The Reapers who have set up the galaxy in such a way that civilizations may develop to a certain point and are then consumed by The Reapers before the cycle is started anew. The synthetic species The Geth treat The Reapers as comparable to gods.