Horrified

Horrified is a debuff which prevents a character from moving too far away from Wall of Flesh when it is spawned. It is only removed when you either kill the Wall of Flesh, or die. Horrified causes the Wall of Flesh to act accordingly: Running too far from the wall and escaping or wedging yourself behind the wall causes The Tongue debuff, where the Wall of Flesh will forcibly reel you into his mouth.

Teleporting away with the Magic Mirror while being Horrified causes instantaneous death upon arrival at your spawn point. The Wall of Flesh, however, will still be active until it has swept across the entire Underworld.