3. Life Model Decoys
Marvel ComicsLife Model Decoys have already been briefly mentioned in the Marvel Cinematic Universe, with Tony Stark jokingly telling Phil Coulson that he was speaking to the Life Model Decoy of himself when he was trying to get through to him on the phone. However, it is the context of a potential mentioning in Age of Ultron that would be interesting - and probably quite unlikely - given the relationship between them and the titular villain of the movie. Ultron has actually been a Life Model Decoy at one point in the comics and it would be very cool if we thought we were looking at Nick Fury or another heroic character, only to find that we had actually been witnessing Ultron infiltrating the Avengers' ranks. Also, in the comics, parts of Ultron were actually used to upgrade the generic Life Model Decoys and it would be cool if, after his inevitable demise in the movie, we see Life Model Decoys for each heroic character being manufactured, with the fact that they were made using the defeated villain's parts being specifically mentioned (mostly because it would indicate that there was a potential threat from the Life Model Decoys in future movies/television shows).