Again, for a reddit challenge, this time the same one:
Okay, I wouldn't suggest doing this often, lest you lose your players.
Here goes: The players have found a tower, or some other structure. It's pretty obviously abandoned but there are preserved - smoked, pickled, etc. - meats there. This should come after a long time out, and be reasonably easy to fortify, so that they have a reason to stop and stay there. The next morning after a feast on these (of course you can't force them to eat them, but it's up to you to give them a good reason for it.) they are awakened by an attack from whatever the local Orc-Equivalent is. When they arrive at the next town, they find that it's almost depopulated. When they ask around they find that the things that attacked you at the structure were taking and eating, and those preserved meats they ate were actually villagers.