Castiel uses Astral projection to display his wings.
Astral Projection is a quite rare ability to extend at least a portion of your body outward to the astral world.
Projecting one's true self can be harmful and chaotic to the outside world, like when angels extend their true form. If a human completely leaves their body, they become much like a living ghost, gaining all the powers that ghosts do (Super strength, Teleportation, Telekinesis etc.) but only after plenty of practice.
Characters with this ability
James Frampton performing Astral Projection with Sam and Dean.
- God - He revealed his true form to Metatron.
- Angels - Castiel projected his wings to Dean to prove what he was when Dean didn't believe him. He did this again to Crowley during a match-off. While possessing Sam Winchester, Gadreel projected his broken wings before killing three of Abaddon's demons.
- Archangels
- Seraphim - More advanced than Angels
- Death - Demonstrated when he was liberated by Lucifer.
- Reapers
- Humans (psychics)
- Witches (via Magic)
- James Frampton - Can project his consciousness outside his body and take others with him, even non-witches.
- Rowena - Through a spell she can project her consciousness outside her body.