My interpritation would be that there is no stacking effect at all. It's just like drowning but without the water. As a tactic I would suggest you keep the monsters a bit apart though so they cover as much area as possible with their separate areas.
I would make pcs unfortunate enough to be on both the two areas to make two saving throws, one for each drowned.
I would make pcs unfortunate enough to be on both the two areas to make two saving throws, one for each drowned.
That would be my ruling for this, too.
My interpritation would be that there is no stacking effect at all. It's just like drowning but without the water. As a tactic I would suggest you keep the monsters a bit apart though so they cover as much area as possible with their separate areas.
I'd go with this interpretation myself. Your not saving to resist the affect of the drowning aura per se - your caught in that with no save at all. What your saving against is some kind of cumpulsion to stop holding your breath.
But what it really comes down to is how powerful is a CR 8 creature and whats the improvement for having more then one. Either interpretation can be argued and it does not appear to be cut and dry so your really left with how dangerous you want to make these monsters. Your players might however start to b~#~$ if tehy have to make six savesw a round - they obvously have no chance of pulling that off. Its for this reason I edge toward the more lenient interpretation - that way you can actually use the background of there being whole islands of ancient civilizations washed beneath the waves of these things without forcing the PCs to fight them at more then 30 feet for the entire adventure.
My interpritation would be that there is no stacking effect at all. It's just like drowning but without the water.
I used this ruling when I pit my PCs against four of these cadavers.
So, I learned the hard way that their listed CR is definately off. What IS their CR supposed to be?