This has got to be one of the best fake trailers I've ever seen, as well as being slightly funny (loving the attack on Morgan Freeman and the end logo arm bit...). It's a faux trailer for E.T. 2 or E.X.T: Extinction as it's been called by the creator and uses scenes from various other movies spliced into one to not only give us the original actors appearing but also a sense of drama and Cloverfield-style sci-fi. Very cool!
Beware it's NSFW!