So I just finished up a gaming session with my DM girlfriend. We’re about 200 miles apart for the summer (which right now is probably a good thing for my sake) and so we played over a mix of text and g-talk voice.
I spent an hour scanning every room of my dungeon into easily send-able .bmp pictures, thinking she would continue to explore around. But no, she wanted to get a shinny glowy thing she found earlier in another room, guarded by a giant bat.
So off she ventured with her main character, the very promising Biffy Dunwhite, esq. and her masterful sidekick Kai Shiradi.
You see, Biffy had heard that there was a giant bat in the dungeon, and so late one night while she couldn’t sleep, she bought a “Bat’s day-fucker-up” device off of QVC, consisting of a bulls-eye lantern and a mirror.
Armed with this great high quality tool he descended into the dungeon with Kai. After coming to the room with the bat, they spring in upon it, startling it. Kai swings at the bat and hits it with a glancing blow, but the bat crushes the fierce warrior down to one hit point before Biffy can aim the light in the bat’s face, sending it stumbling backward. Enraged, with Kai bleeding her guts out all over the floor, the bat charges at the hapless Biffy, and in one swoop kills her. Kai drags herself up and staggers towards the bat, now standing over Biffy’s lifeless body, between her and the door, she swings, but given her weaken state misses horribly. They bat turns around and finishes her.
And thus ended about 10 minutes of game play after about 3 hours of preparation. (The player’s fault) This is my first dungeon, and I was really hoping not to kill off my girlfriend’s characters, but apparently I didn’t know how strong of a monster the giant bat was. It has 8 hit dice, a challenge level of 9, and 1,100 xp…..my bad……. The rest of the monsters are just goblins of one variety or another, and I thought a giant bat would be cool. Little did this new DM know how un-cool it would be for Biffy.
The Godless Paladin 
Now to be fair we’ve all done this; though mercifully I’ve never managed to TPK a party before they managed to get out of there. I’d be tempted to keep your favourite PC out of harms way for a while though, lest ‘rocks fall’ and everyone dies.