A typical wand with offensive capabilities (magic missiles, fire, fireball, lightning bolt) that was either damaged in combat or made just under par. When the wand is discharged, there is a 1 in 4 chance that it fires an additional 1d6 charges simultaneously or in rapid succession. Wands that shoot fire may incinerate innocents and friendlies, or burn whole buildings and even villages down. Those which shoot fireballs have a considerable radius, and lightning bolts that bounce upon contact with ground and stone can cause catastrophic random collateral damage. Those who have paid large sums for such a device may go seeking a refund, possibly even retribution.
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.
One day a a wind begins to blow out of the West. The next day it gets stronger. And stronger still the next few days. Eventually (and fortunately), the speed of the wind tops out at a steady fifty miles an hour, but continues to blow. Soon an entire kingdom is wondering why it's not abating. The weather mages deem it unnatural but can't seem to banish or control it. The priests of various faiths claim it's divine. The End-Of-Days crowd is having a field day with their predictions of doom. No one knows why the gale persists. When inquiring with neighboring kingdoms, it seems they too suffer from a persistent western mistral. Eventually the populace begins to adapt to living with a twenty four hour a day wind. Always from the West, and perpetual. What could be causing this? A raging Elemental king? a curse from the gods? an unearthed artifact? Or has Nature itself gone haywire?