Last night may have been our worst Index Card D&D dungeon dive ever.
In the first room of the dungeon, the Bakers Guildhall, a fire-breathing frog that splits off another fire-breathing frog showed up along with a giant block of ice that kept us from moving forward. One of the party members had an ability that let him try to possess monsters, so he possessed the frog to melt the ice cube. We finished searching the room, and Feyd-Rautha popped out of a cupboard and challenged the guy possessing the frog in a one-on-one fight to the death. The guy possessing the frog tried and failed to possess Feyd, and the next thing you know, the room is full of drunk, fire-breathing frogs and a belligerent Harkonnen.
We fled deeper into the dungeon, and after taking care of the first group of weaker monsters, Zargon showed up, with his 12 hit dice and seven attacks. We ran deeper still, losing half the party to free attacks.
I had to leave right after the party ran smack into an evil cleric/anti-paladin lady with the silver hammer and two harpy body guards, but I’ll bet at least one more person died!