Ok, we tried to leave the title as spoiler-free as possible, but there will be spoilers in this article. Of course, pretty much everyone has seen The Avengers by now, and what we will be covering has been discussed openly in a number of cast and director interviews on various entertainment sites. Everyone pretty much knows by now that Agent Coulson was killed by Loki in The Avengers. Or was he? There are numerous rumors circulating online that Agent Coulson isn't really dead. While death is usually final in most movies, the same rules don't apply in comic books. And since The Avengers is a comic book movie, maybe dead doesn't necessarily mean dead. Here are five theories on how Agent Coulson could return. 5. Loki Illusion – Remember how Loki tricked Thor into entering the glass and steel cage with an illusion. What if Loki decided that Agent Coulson would make for a valuable prisoner and just created an illusion of Agent Coulson dying as a distraction? Of course, Nick Fury would have eventually realized it was just an illusion, but maybe he kept it secret to motivate the Avengers. 4. Coulson Replaced By A Chitauri – In the comic books, Chitauri are a shape-shifting alien species. Just because the Chitauri aren't shown using their shape-shifting ability in The Avengers doesn't mean that they don't have that ability. What if Agent Coulson had been secretly replaced by a Chitauri? Of course, that raises the question of why he would attack Loki if he was really a Chitauri, but maybe it was all part of Loki's master plan to create chaos within The Avengers team. 3. Coulson Saved By S.H.I.E.L.D. Technology – We know that Nick Fury is a master manipulator, so are we really going to take his word for it that Agent Coulson died? What if the S.H.I.E.L.D. doctors were able to save Agent Coulson, but Nick Fury just pretended Coulson was dead to motivate The Avengers? 2. Life Model Decoy – Early in the movie, Tony Stark tried to convince Agent Coulson that it was his Life Model Decoy answering the phone. While this seemed like a throwaway one joke line, what if it was purposeful to reveal the existence of Life Model Decoys in the Marvel movie universe? Could it have been one of Agent Coulson's Life Model Decoys that was stabbed by Loki? 1. The Vision – Probably the most interesting theory about Agent Coulson returning is that he will come back as the android The Vision. The rumor seems to have originated just because Clark Gregg, who plays Agent Coulson, kind of looks like The Vision. However, it has been gaining steam over potential Avengers easter eggs. Some are speculating that Nick Fury calling Agent Coulson his "one good eye" was a hint at The Vision. Others are claiming that Scarlett Witch, who was Vision's wife in Marvel Comics, was a cellist, which would go along with Agent Coulson dating a cellist.