The Crimson Bands of Cyttorak is a spell that is dependent on a demon called Cyttorak. By tapping into the power of Cyttorak a sorcerer can summon mystical strands of energy that combine to form a mystical force field.
History
Baron Mordo used the Crimson Bands of Cyttorak to protect the Center for Reunification. However, Doctor Strange was able to invoke the Hosts of Hoggoth to remove the Crimson Bands of Cyttorak and he, Wong, and Spider-Man went inside to battle Baron Mordo.