A small group of cannibals has started roaming farther out from their remote home and have come into contact with some farms.
The heroes find a small crypt somewhere and being brave adventurers they want to check it for evil forces (=graverobbing). Or for any other reason.
As a mage walks through the forest a sprite appears on a branch in front him (or her). The mage will be the only one that will be able to see the sprite. The sprite demands that the mage release him from the forest.
On the outskirts of a poor looking village is a large mausoleum that is well kept and richly deserted. It has a marble walkway and bricked windows with beautiful ironwork adorning it. For grave robbers the look of the outside tells of untold riches on the inside.
In a village the characters hear rumors of a man that recently came through screaming of demon attacks and murderous insects.
A large explosion was heard 4 days ago coming from the foot of the nearby mountains. Ever since then no trade wagons have come through as they usually did.
Bag on a Stick
Very simple gag but a great one, since it can be used multiple times over, even in the same adventure. Great for tribal natives gone restless and humanoids, but anyone can have set this up. Just what the header says, a simple bag over a stick stuck in the ground or floor.
As GM you can place the bag on a stick anywhere, in a floor crack the heroes have passed before, outdoors in a clearing or path, or at the edge of the PCs' encampment the following morning, what have you. Place anything on the stick - a coiled yellow viper angered by the bag removal, mini crossbow w/poison, transdermal hallucinatory drug dusted on the bag, yellow mold colony, an NPC ally's head, a weapon, scroll tube or satchel, what have you.
The idea is to build tension and/or stall for time/distract the party. Provided it's used properly, you'll be amazed at how paranoid players will get from this simple gag.