Sigil Trap Necklace
A standard devil's trap, often used by the Winchesters against demons.
Sigil traps were various magical sigils within circles, that, when drawn somewhere, could render its respective supernatural being unable to leave, use their powers, or destroy the circle directly in any way upon entering. However, Castiel had been shown to have used Meg as a mat and walk across her to escape his trap made by Lucifer.
