Unknown Armies - Seattle
An old box and its contents...
This is an old cardboard box. Its bearer may use any mundane cardboard box in the vicinity to enter or leave the Cardboard Palace, through any other mundane cardboard box within a mile.
If it is crushed, the walls and rooms of the Cardboard Palace collapse together, giving anyone inside a slim chance of escape. If it is set on fire, it burns as if soaked in strong spirits and the nearest cardboard box becomes linked to the Palace, and (presumably) everything in the current Palace is engulfed in flames.