From an episode of Justice League Unlimited:
The God of War creates a giant, unstoppable robot (golem, animated armor, etc.) as a weapon for one side in a civil war; his purpose is to prolong the war and create suffering and war among humanity.
Quote from Ares in that episode, which would go well with this idea: "That's all you mortals are good for! To fight and fight and fight until there is nothing left but charred land and blood and bones, and to end it all and then start again with the next generation!"
Loud war-screams shatter the silence of the forest. The party, scrambling quickly over the thick forest floor, are ambushed by savage elves, dropping down from the trees and rock outcroppings. Their hair is cropped into mohawks and their arms are striped with tattoos.
They attack, and scalp unfortunate victims.
Recently, agents of a necromancer's guild known as the Guild of Morticians have been seen slinking around the graveyards in the metropolis of Jeffsport. They have been seen with many small undead creatures, leading to speculation that someone may be digging up the corpses and selling them to the Guild of Morticians. The Jeffsport Civil Authorities Office and various splinter groups thereof, including the famous Blue Lampsmen (the Jeffsport city guard), have issued a bounty of 100 silver pieces for information leading to the capture of whoever is selling the corpses to the necromancers, and a 30 gold piece bounty on any member of the Guild of Morticians.
The heroes have destroyed the minions, plunged through the catacombs and defeated the guardians. They slowly enter the chamber to find the dark mastermind behind the scheme. The mastermind has a request for them, however:
"You must destroy me. To destroy me is to rid the world of a great evil, that is to say, me. But before you can destroy me, you must understand what evil is, what evil must be, why evil must exist."
Five stone dead beholders encased in bronze are found in nets on the side of the road.
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.