I recently had a conversation about a RPG mechanic that I have almost never seen used: the geas.
For those of you lucky enough to have no idea what a geas is, it’s compulsion that forces the victim to do something regardless of their own agency. It might be a magic curse or a chip in the brain or a jewel in the skull. It can fit into many genres but it does the same thing regardless of its name.
(In fact, I don’t know if there’s a specific term for this mechanic. It might well be geas and that word does work awfully well)
Now, I am not entirely against rail roaring. In some mediums, rail roading borders on a necessary evil like game books and certain formats of video RPGs. (Although the ability to have sandbox open worlds is indeed a triumph of the medium) If you know what you’re getting into, you can have fun while being rail roaded.
But the geas is a different beast. It doesn’t dictate the plot of the game but the actions of the players. And that isn’t fun. I can think of only one game I was where that happened. The GM’s goal was to have everyone try and kill each other. (And, no, we weren’t playing Paranoia. Again, with Paranoia, you know what you’re getting into so it’s cool)
Honestly, the only way a geas works positively is when players are trying to get around it, subvert it. But that requires the GM willing to let folks be clever.
There’s probably a reason that geas stays almost entirely in fiction, not games.