Day 2: implemented a controller system to be able to impersonate any monster, and the possess spell which makes use of it. Also added a few story screens when starting a new game.
As for mechanics, I settled for:
- the possess spell only works if you are alone with the monster close to you, for a few turns (monsters will try to stay grouped to avoid that, spells like confuse may help you)
- when you unpossess a monster, it might come for you with a lot of anger
- no healing is possible, so that you have switch bodies often
- one problem I foresee is trying to bring with you multiple utility bodies. To avoid that monsters will have a non-trivial chance of dying when unpossessed
- the inventory stays with an unpossessed body (maybe I will start with no inventory at all)
The trick is to create situations where possession is an interesting mechanic. For example, you have to cross a lava river. A bat is on the other side so I can drop a fruit on the floor to attract and possess it. Or I could use a fire elemental which is immune to lava. However there is none around, so I possess a sorcerer who has the spell for summoning one. Unfortunately he doesn't know the spell, so I bring him to a library and "convince" the librarian to give me the scroll.
This looks like it will be difficult to setup generativelly but I have ideas...