Arising from polluted cemeteries and other recesses of stagnated evil, these areas of heavy, corpse-gray fog reek of rot, and seem to have a strange and malevolent sentience. These fog banks act as normal fog, but usually have a radius of 1d4 × 50 feet and creep along with the wind at a rate of 10 feet per round. When the fog comes into contact with a mostly intact corpse, that corpse is immediately animated as a zombie and attacks nearby living creatures, as if under the effect of animate dead. This animation is temporary, ending 1d4 rounds after the zombie leaves the fog. Corpse fogs can animate up to 30 Hit Dice of corpses in this manner at any one time, and they have no limit on the total number of Hit Dice of zombies they can animate over time.
Some particularly foul and virulent variations of this fog (CR 7 instead of CR 6) produce plague zombies instead of normal zombies. Creatures slain by the plague zombies’ zombie rot who rise as zombies don’t count against the fog’s limit on the number of Hit Dice it can animate, and they remain zombies after the mist passes. Diseased animating fog also exposes every living creature within the fog bank to zombie rot each round as an inhaled disease (Fortitude DC 15 negates).
Pathfinder Roleplaying Game Horror Adventures © 2016, Paizo Inc.; Authors: John Bennett, Clinton J. Boomer, Logan Bonner, Robert Brookes, Jason Bulmahn, Ross Byers, Jim Groves, Steven Helt, Thurston Hillman, Eric Hindley, Brandon Hodge, Mikko Kallio, Jason Nelson, Tom Phillips, Stephen Radney-MacFarland, Alistair Rigg, Alex Riggs, David N. Ross, F. Wesley Schneider, David Schwartz, Mark Seifter, and Linda Zayas-Palmer.