Binding Link
From Super-wiki
A binding link is a symbol which keeps a demon trapped inside its Meatsuit i.e. the human it is possessing. The demon can neither escape voluntarily of be exorcised.
File:Binding link.jpg
Binding link used by Meg on Sam
2.14 Born Under a Bad Sign
When Meg possesses Sam she brands a binding link into his forearm. When Bobby tries to exorcise her, it doesn't work. Bobby realises the brand is keep her trapped inside Sam, and burns across the mark with a hot poker, breaking the spell.
5.20 The Devil You Know
Crowley: This bit of carving will tie our friend her down. No zapping off, locked in the meat suit. An important part of our bargaining strategy.
Crowley carves a symbol into Brady's chest while they try and convince him to help them.
