#Dungeon23 Tomb of the Vampire Queen, Level 3, Room 24

Further down the hall there is a cell to your left. 

This cell is filled with a thick green haze/mist. Visibility, including dark vision and infravision, is reduced to 1 foot. 

After 1 round the mist will start to poison the PCs.  They must make a saving throw vs. Poison or be rendered unconscious. Any unconscious PC will loose 1 point of Con every turn until they are taken out of the mist. Any character reduced to 0 Con dies.  An unconscious character will revive in 1 turn and be back at normal Con with 1 hour of rest per Con lost.

I the character makes the save, their Con loss is 1 point per hour. These characters will regain Con at the rate of 1 point every 30 mins of rest.

There are three skeletal remains from previous victims here. They have 200 gp, 300 sp,  55 cp, five gems of 5 gp each, and a dagger +1.