User blog comment:ADour/Official title for Marvel's The Avengers sequel announced!/@comment-1671874-20130721222300/@comment-1895174-20130725235659

The 2008 film has an origin for the Hulk similar to the Bill Bixby / Lou Ferrigno show from the 70s - a science experiment gone wrong, namely that he gets bombarded by much more gamma rays than he signed up for.

Ultron being some trick of Loki's is a cool idea. You haven't seen IM3, so I can't say much more, but you should get on that.