Nearly a TPK last night. Things that went wrong for the players:
a. The fight was lost before they entered the room. Because they walked into a room where they'd be surrounded by stuffed monkey-fish. How can they NOT be animated monsters? I think I know what went on - the players were completely focused on what to do with that 5' long gold T-Rex tongue and ignored my descriptions.
b. And yes, the tongue is also a trap. Come on! It's a gold tongue inside a T-Rex skull! How can it NOT bite you? Well they haven't triggered it yet, probably next session someone'll get chomped...
c. Once combat began, it went poorly from the first round, but the players refused to retreat until round 4, with almost everyone dead. How things were suddenly going to turn around after the henchmen started dropping, I don't know. The clerics (Leroy the henchman and Gutboy) went down with almost no use of their heal spells - Gutboy spent the entire combat fooling around with his pet dog, healing it and removing its muzzle, and then watching helplessly as it was gutted by Feejee mermaids.
They managed to pull out of it alive, but are in a really bad spot, though, as any wandering monster will probably take the lot of them out, unless Dr. Giggles saves Gutboy. That's a big "if", I've got a table of surgical results to write up now, most of them unpleasant. I didn't want to do it on the fly, and I hadn't written up the Dr. Giggles part of the dungeon yet, and it was late, so I ended the session on a cliffhanger.
I hope they get a bit more cautious in the next session... I want them to succeed, but I will slaughter their characters as the dice demand.