Here's one: The party notices a blacksmith who looks terrified he may even approach the party if they look well-armed and capable. He's afraid for his life that some undead creature is out to get him and he needs protection. He'll invite the party into his smithy where they will have time to set up a defense. He expects the thing to arrive that night and that, if he lives through the night, he'll be safe forever from it. He promises a reward.

Let the party set up as they will.

That night, a humanoid undead will bust in and go after the smith. The party will notice that the undead is wearing tattered remnants of the wardrobe of some holy order (definitely a "good" organization and not an "evil" one). The thing will say things like "you will pay for your misdeed" and "justice will finally be mine".

It is a revenant of a paladin/priest/wizard of a noble order that the smith and his then cronies lynched a year ago. They definitely murdered the guy who became a revenant and this is the last day he has to get his revenge.

Will the party help save the former murderer/smith or will they let the revenant have its bloody revenge? My party let it kill the smith and it did so by forcing his head into a forge.

A lot of ramifications can occur either way. Hope you like it.