I’m making a Mod

I'm planning on making a Clangen mod where cats can get possessed and kits of possessed cats get possession immunity and special personality traits. Other mechanics will be a mass extinction event called the great dark, Possession sickness which will be highly lethal. Poisoned predators and rabid prey, higher chance for Starclan events that result in possession. And other things, It'll be like a form of hard mode for Clangen, does anyone have some ideas for special events? Or any interest in using something like this in a Clangen story?