Thanos first appearance in The Avengers - The Avengers Movie Ending + Post Credit Scenes (HD)

Rogers, Stark, Romanoff, Barton, and Thor rally in defense of New York City, the wormhole's location. Banner arrives and transforms into the Hulk, and together the Avengers battle the Chitauri while evacuating civilians. The Hulk finds Loki and beats him into submission. Romanoff makes her way to the wormhole generator, where Selvig, freed from Loki's mind control, reveals that Loki's scepter can be used to shut down the generator. Meanwhile, Fury's superiors from the World Security Council attempt to end the invasion by launching a nuclear missile at Midtown Manhattan. Stark intercepts the missile and takes it through the wormhole toward the Chitauri fleet. The missile detonates, destroying the Chitauri mothership and disabling their forces on Earth. Stark's suit runs out of power, and he falls back through the wormhole just as Romanoff closes it. Stark goes into freefall, but the Hulk saves him from crashing into the ground. In the aftermath, Thor returns Loki and the Tesseract to Asgard, while Fury expresses confidence that the Avengers will return if and when they are needed.