Someone has released a hoard of rust monsters into a large city and the monsters are destroying all of the tools and weapons crafted by the blacksmiths.
The party discovers an ancient book that lists the names of thousands of people and how they died. The next time they open it they see an entry written for each of them.
A tinkerer runs into town frantically yelling about a contraption gone wrong. Shortly afterwards a massive golem reaches the town and begins destroying everything.
A local brewery hosts a drinking competition to see who can drink two tankards of their ale the fastest. Shortly after the competition, everyone who drank the ale begins to fall unconscious on the ground.
An enormous fissure opens up in the middle of a town and a green mist begins to pool out of it. Everyone caught in the mist begins to slowly walk towards the fissure until they jump to their death.
A horse runs into town with a dead man tied to its back. The man is covered in blood and appears to have a sealed note tucked into his mouth.