In the making of Doctor Strange, director Scott Derrickson and his team were tasked with bringing to life the classic Marvel villain Dormammu, and the direction they ultimately decided to go with it is bold and epic. Playing into the character’s god-like dominion over the Dark Dimension, the film features him as a threatening and imposing being that also happens to be largely formless. In retrospect it was a great choice, as it works rather perfectly with Dormammu’s role in the blockbuster, but it’s also cool to think about how the blockbuster may have been different with an alternate design.
Article source: https://www.cinemablend.com/news/2493048/doctor-strange-concept-art-reveals-dormammu-could-have-looked-even-creepier