This thread is reminding me of the game Everything (here's a gameplay vid). It's a simulation game and you can change your perspective to any object in the environment, whether it be a tree, animal, snowflake, planet, or the entire universe, and then move through the simulation. You can also combine with others of the same object and then as you move, each object that is a part of "you" moves with you.

I have had zero transformation experiences in my dreams, but I thought this would be cool to share.