Gungho officially announced the Beezlebub descended dungeon details and times earlier on their website. The dungeon will be open from 10/20 at 14:00 through 10/21 at 13:59 Japan time. There will only be a super hell class difficulty for the dungeon, and you can see the first official images from the dungeon below. There will also be a Max Murai challenge for the dungeon, where if he can obtain a no continue clear everyone will get 5 free stones. It will be webcast on the weekly Niconico live web show. Stay tuned for further details as they become available.