A great idea I had the other day is to have a rescue mission instead. It will be a different idea than just the old Piggy-style game. Maybe a friend accidentally entered a hole or a cave where they get kept hostage by a demon or a killer.
However, don’t tell too much information to your players as it will kinda ruin the horror mood. One of the most key things is the fear of the unknown. So, what you can do is just give them:
Stacy is nowhere to be seen, maybe she went in this cave nearby…
That’s as vague as it’s clear. Players know to rescue Stacy and get out, but we don’t tell them that there is a demon (which a horror game probably already insinuates that) nor as to how Stacy got trapped.
And you did say multiplayer, right? IDK about you, but if I was playing a horror game and I was alone, it’d be 10x scarier than being with other players. Not only that, but some avatars are so hilarious it ruins the mood for good. What you can do to keep the mood and make it multiplayer is to separate your players from the beginning. Like they spawn at different places and the place is big enough that they usually don’t meet up as often. Something to add to this is some text saying:
Huh? Where did everyone else go? I swear they were right behind me…
This leaves your players feeling helpless and afraid (just what we need muahaha).
IDK if you’ve read it already, but here’s my tutorial, if you want some more information:
BOO - The 3 Prime Elements to Spice up Your Horror Games!