“ In this dungeon, the monsters will not be hostile unless you take something without permission. If you do take something, the monsters inside will consider it stealing and attack you.”
“ A casual remark by one of the party about something met on a previous adventure leads to a summons to and grilling by the Mages' Guild (or equivalent), probably resulting in an expedition back to that area to recover the things for study by the Guild. The party's presence will be 'requested' for this expedition.”
“ A planet (or city, valley ect) where those who enter witness protection can escape old age and death itself, so they can live for centuries without aging-provided they maintain their cover perfectly. If they are outed by anyone or ever utter their true name, they age the number of years they have not aged since the day they entered witness protection (which might mean that they age centuries in seconds and crumble into dust and bone.)”