The Bell of Opening is a unique item you encounter during the Quest (along with your role's quest artifact). It is one of the items needed for the invocation. It is a silver bell when unidentified, and can be used as a silver weapon if need be. Hitting things with the Bell equipped does not break weaponless conduct.
When applied with charges, it will detect secret doors and traps in your visual range (including magic portals), and cause you to be spit out if engulfed (like a wand of opening). If blessed, it will additionally open things (doors, chests, drawbridges, etc.) If cursed, it will not have any of these effects; it will instead summon undead and wake nearby monsters. If you apply it when it has no charges, it acts as a normal bell.
The Bell starts out with three charges. If you use them up, you will have to charge it up before doing the invocation. In addition to the invocation, it is useful to find the secret door along the temple wall in Moloch's Sanctum.
The Bell of Opening cannot be put into a container and is impossible to destroy, like all invocation artifacts.
"A bell, book and candle job."
The Bursar sighed. "We tried that, Archchancellor."
The Archchancellor leaned towards him.
"Eh?" he said.
"I _said_, we tried that Archchancellor," said the Bursar loudly,
directing his voice at the old man's ear. "After dinner, you
remember? We used Humptemper's _Names of the Ants_ and rang Old
"Did we, indeed. Worked, did it?"
* Old Tom was the single cracked bronze bell in the University