A relentless and unearthly durable type of dimensional fatigue 'denizen'
It's always the creepy little kids
They came upon us suddenly, no sound preceding them until the splashing of their feet drew our eyes towards them. The wolf-things neither howled or snarled as they tore into our ranks.
The PCs are walking along the road, when suddenly a bunch of bandits attacks. The player's dismiss it has just a random encounter, when they find an ornate ring on the leader, obviously out of place with the seemingly poor bandits, who could only afford cheap leather and weapons. This ring has a symbol on it, which, if researched, sets the PCs on a quest. And from then on, the players don't look at random encounters the same way...