I dont want to spoil the show too much, but there is an alien element to it that is pretty much the main storyline. You first learn about it early in season one, maybe even episode one. Its an alien technology thats biological in nature. No one knows how it works exactly or what its objective its, but it clearly has some sort of conciousness as it reacts to actions by characters in the show. Its not safe for humans in its pure form, it invests the body eventually consuming them. Whether their conciousness exists or not once consumed is up for debate. Video explaining the protomolecule. (Spoilers) submitted by /u/encinitas2252 [link] [comments]