I'm looking for the name of a critter from a Dungeon adventure from the late 80's-early 90's. I believe the adventure was a side-trek and the setting was an inn in the wilderness. It was supposed to be an eerie adventure, and the PCs were supposed to figure out what the critter was that was sucking the blood of the other travellers. It turns out that the critter was a blood sucking ooze, and it was hiding outside in the wet snow between feedings. At least that was what I remember. What was the name of the adventure, the issue, and the name of the big bad ooze, and where was it found? I'd really like to use the monster elsewhere, even if I have to convert it to 3-3.5e, but I can't remember what it is! :\ Help?