Slaad, then
Alright…
Mid-afternoon-- the PC party comes across a remote village. The whole town is quite, and appears deserted from a distance. Crows flap their wings and caw from roof tops, and a pack of feral dogs can bee seen tearing into what appears to be a corpse as the PCs approach the outskirts of the village.
Late afternoon--as the PCs get closer and begin to explore the village, they find a half-dozen of villagers, all with their chests blown out from the center, like something tore its way out from the inside. The town shows clear signs of fighting, and several huts have been reduced to smoldering ruins. The corpses scattered about can’t possibly account for the entire village though, so surely someone is hiding somewhere…
Evening—the PCs begin to notice that something or someone is tracking their movements through the village. Eventually they discover a young girl, who beckons them to her. She warns them that it is not safe to be in the village after dark, and asks them to follow her to a place of safety.
She leads them to the basement of the old mill. There are a handful of other survivors, including the village priest. The priest takes them to a cooled locker, where there are another dozen or so comatose people lined up, all under an altered version of the preserve corpse spell the priest was able to work out with his god. The priest explains they have all been infected with whatever it is that killed some the villagers above. He says that horrible monsters had burst through their chests, killing the host and slaughtered dozens of other villagers, dragging them off into the darkness to feed.
Through the battle during that first night, the priest as able to organize some of the village members to put up a resistance, but most of the town was slain. The next morning, before the PCs arrived, the survivors crept out and found the few villagers left up top, all of whom had been implanted with slaad eggs (the priest doesn’t know this is what’s going on, he just knows something is inside of them). The priest had these comatose people brought back to the basement of the mill, where he was able to put them in a sort of stasis. However, he knows his preserve corpse spell is weakening, due to the magical resistances of whatever is incubating inside their chests.
Nightfall—The PCs are now trapped in the basement of the mill with the priest and his fellow villagers. They must fend off the onslaught of 5-6 slaad, hoping the preserve corpse spells don’t fail and they are not attacked from the inside by even more slaad as the eggs hatch and new slaad burst forth.
If they succeed, can they find a way to “cure” the remaining villagers? Is it possible the originator of the infestation is IN THE MILL with them, disguised as one of the surviving villagers?