By far the best way I’ve found to use the false Hydra so far is a week or two ahead of a session, to send out a link about the false Hydra to your group and be like “look at this neat monster I found!” Then present them with a story about people disappearing from a village and watch them invent their own false Hydra.

For those of you who haven’t already read the goblin punch blog post (which is linked in this post but is easy to miss), I strongly urge you to read it. It’s a bit long but it explores the concept of this horrifying monster in a really interesting way.

As for actually running a false hydra… I dunno. It would be amazing if you could pull it off, but I think it would be a lot of work to set up if you’re trying to manage real-life player memories as well as character ones.