I am running a campaign that is tied heavily to lovecraft. I got the idea of using Passive Perception as an actively changed stat, like HP. The new premise of the stat I am proposing is as follows:
- If passive perception (P.P.) reaches 0, you go (completely) insane and die.
- A failed death throw lowers P.P. by 1.
- You can fail as many death throws as you like, so long as you have the P.P. to supply them.
- A long rest restores P.P. by one (up to a max 10+Wis_Mod+Int_Mod)
- Items, and events (eg: not sleeping) can lower and raise P.P.
- P.P. Has the same functions as Vanilla P.P. in addition to these rules.
How this ties into Lovecraftian horror, is that a player with lower P.P. Will perceive the world differently, and start to see more of the 'bigger picture'. For example:
Adventurers come upon a man that is convincing them to save his burning cottage.
- P.P. 15: The man is a peasant whom likely doesn't have much wealth, judging by his fashion. It would be noble to complete this deed, but likely without reward.
- P.P. 10: The man seems to be in dire need of this favor, as he is pleading very well, but something seems awry.
- P.P. 5: Something anomic has set this cottage afire, and this man is no ordinary man, he seems to be heavily influenced by a force.
- P.P. 1: The cottage contains a fire, and an abhorring entity, you know not its intentions, but fear rushes over you. Why is your party simply standing there? (Note no descriptions about the peasant)
As you can see, the Passive Perception stat changes what people make of the world, and is an integral part of the gameplay. It has an ebb and flow mechanic, where P.P. is a slow stat to move.
This is intended to be new-player friendly, so I think that letting a character fail 10 death throws off one fight, at the cost of sanity is not a bad thing. It provides punishment, but softens the blow of a failed throw. I don't plan on using this to try and draw apart my PCs, but give different observations of the same reality.
So, My question
What trouble does this active altering of passive perception cause for My PCs?