“ In one region of a forest, all of the trees are identical, down to the leaves and the twigs. If the PCs carve something into one of the trees, it could mystically propigate until it covered all of the trees, or could vanish since it was not carved into the one true tree.”
“ Something lives in the fog in a certain region and travels with the fog. Kidnaps or kills, or is simply heard and 'felt'. ... fog is rising, heed the warnings the elders spoke!”
“ A wizard has cast a slow action freezing spell upon a PC. The air gets colder around the PC by one degree a day. If the spell is not broken within a few weeks the PC will freeze and die.”