Thread:Shabook/@comment-30528847-20161121173954/@comment-112155-20161121174502

Marvel doesn't need to explicitly state that their movies tend to follow basic physic laws, such as that a body with lower density than the air is able to float... And controlling the density of only some of his body parts explains the Ultron sentry fact.

On the other hand, it coming from the Mind Stone is strictly your speculation, nothing in either movie he appears leads to that...