Due to studio pressure and the demands of juggling umpteen storylines at once, there’s a lot in Avengers: Age of Ultron that doesn’t make sense. Especially confusing are the film’s many dream sequences, the most inexplicable of which sees Thor leave his super-squad and join Dr. Selvig on a jaunt to a creepy, mystical, underground cave pool. In the movie’s theatrical cut, Thor wades into said pool, has a vision that involves Infinity Stones, then rejoins the Avengers to defeat Ultron.
Needless to say, the Asgardian’s trippy dip in the grotto seemed rather random. But now we have this deleted scene, which doesn’t explain what the pool is, or how Thor knew about it, but at least lends some much-needed context to the moment. In this version, Thor takes a fortifying swig from his flask before being possessed by a Norn, one of three female beings who control the destinies of both gods and mortals; Selvig then asks Norn-Thor a few questions that illuminate the broader plot and trajectory of the Avengers movies. To my eye, the scene is a lot better than what ended up on screen, but Joss Whedon explained on The Empire Podcast why it never made the final cut:
So Chris [Hemsworth] got to do something different, and he really threw himself into it, and he did a beautiful job, but it wasn’t well regarded by the test audiences and I feel it’s probably largely because it was a rough cut with no effects, but also because it’s something that in a Thor movie would work brilliantly, but in this movie is just a little too left of centre … The dreams, the farmhouse, these were things I fought [for]. With the cave, they pointed a gun at the farm’s head and ‘Give us the cave’. They got the farm. In a civilised way – I respect these guys, but that’s when it got really unpleasant.