Hell's Bell is an artifact that is often associated with Hell's Bell-Ringer. This is an unbolded artifact but is an incredibly important object in the eye of Hell's Bell-Ringer.
Hell's Bell is used by Father Enki to call evolved souls to Hell. This item has been known to cause an ear-splitting shock when hit correctly. However, this theory has never been tested as no clean Hell's Bell has ever been found. In order to protect Bell's Bell from ever being used improperly by heroes, monsters cover the object, as they die, with a sticky substance that renders the object useless, which is why it is not bolded.
This item is still in high demand with collectors of rare demonic artifacts, however, and can still be sold for a decent amount.