Mysterious Jar
The Mysterious Jar features in a mini event. There are three jars, two smaller ones that contain Dune Dervishes and a larger one that contains a Superunique Dervish called Pazuzu who drops a few items once dead.
This event can appear as a Bounty in Adventure Mode too but as of April 2014 is bugged and Pazuzu doesn't appear preventing you from completing the Act II Bounties and collecting the Horadric Cache.