Source Pathfinder #27
Aura moderate conjuration (masked by ...?; CL ???
A Devil's crux is similar to a bag of holding in that its interior space is larger than its exterior would suggest. When closed, a Devil's crux is a wooden and metal dodecahedron (similar in shape to a d12) that measures about 6 inches in diameter. Each face of the crux is carved with a different rune or image — in order to open the puzzle box, a person must trace the outlines of these runes and images with the tip of a finger in the proper order. Each time a rune is triggered in the correct order in this manner, it glows with a soft red light, but whenever a rune is triggered out of order, the light flashes into fire and inflicts 2 points of fire damage per currently lit rune on the person attempting to open the crux (Reflex DC 15 halves) and causes all lit faces to deactivate (forcing the process of opening it to start anew). Failure to open a crux eight times in a row causes the combination of runes to randomize to a new combination. You can simulate this puzzle for the PCs by determining the order in which the runes must be activated and then having the players stumble through the combinations, or you can allow a character a DC 35 Disable Device check or a DC 25 Intelligence check to try to open the puzzle box — each attempt takes 1 minute, and the check can be retried with a cumulative +1 bonus on the roll, to a maximum bonus of +7, after which the crux resets its order (at which point the bonus reverts to +0 and the character must start anew). Failure on either of these checks causes the crux to flash with fire and causes 2 points of fire damage (Reflex DC 15 halves), plus 2 points for each failure.
A Devil's crux can be forced open with damage or a DC 28 Strength check. The crux has hardness 10 and 30 hit points. If a crux is forced open in either of these two ways, it explodes into a 10-foot-radius burst of fire, inflicting 3d6+6 points of fire damage to all within the area (Reflex DC 15 halves). The fire damage affects any objects held within the crux as well. If forced open, the crux crumbles to ashes and any objects it contains appear on the ground at the site of the fiery burst.
Once a particular crux’s combination is known, a character can open it automatically (this takes 3 consecutive full-round actions). Opened properly, the crux unfolds into a 2-foot-square flat sheet of metal and wood. Any objects the crux contains sit upon the center of the sheet. An unfolded crux automatically folds as soon as a character attempts to bend any of the sheet’s four corners as a move-equivalent action. The crux automatically folds up around any objects that sit upon its face at this time — objects that would exceed the crux’s capacity are pushed gently aside by the refolding action.
A Devil's crux can hold up to 200 pounds of objects, but the physical size of each object is irrelevant — the sight of a crux folding up around a long polearm, for example, might make one assume the weapon was crushed and destroyed, but when the crux is next opened, the pole arm is unharmed. As an object that creates an extradimensional space, a Devil's crux functions as a bag of holding for determining how long a living creature within can survive, or for what happens when the crux is placed in another extradimensional object like a portable hole.