You and some other investigators have been asked to the miskatonic arctic research station to look into some strange happenings when suddenly you hear a loud noise and the generators begin to fail. The freezing cold elements slowly begin to overtake the research facility, and you discover that one of the NPC researchers are not what they seem. Someone is infected with a terrible horror and you need to find out who it is and put them down with the flamethrower before they can spread it to the other researchers or one of the investigators. Light fires to survive the cold but beware they don't spread out of control, beware the darkness for there the infection can spread, or the creature it has become can strike.
I don't know enough lovecraft lore to know if there is something that can infect people and change them into terrible things, so maybe FFG would have to make something up, but a mansions scenario that could capture the paranoia and tension of John Carpenter's The Thing would be amazing. I have some ideas on how NPCs and infected players could infect other players without giving themselves away, but I bet that FFG would probably have a better idea than me.
... one day I'll get back to making more MOM Emotes.