My players found out there was a huge bounty on the head of a serial killer "The Seven Cut" and decided to go after him, because money. So they went to visit the most recent scene of the crime. Needless to say it was a gore filled mess. Body splayed open torn to piece the guts removed and stuck to the walls with the finger bones of the victim. Blood literally covering the walls and the moment they went to a crime scene some music started playing . They had a quick look over the place and noticed one of the locks of a vacant building had been tempered with. So they opened the door and there were barefoot footprints left in the layer of dust. They went one way towards the dead end alley. They question the guard for more information.

The guards say that no one was seen coming out of the alley. Now the pattern for the seven cut is known it kills seven women then seven men in a seven pointed star shape. With 13 victims as of late the next place the seven cut is easily predicted, by the players so they lay in wait. Again the music plays. Two people wait on the roof, two on the ground in a nearby alley. The guards (Not being total dumbasses) have set up on the roof opposite as they await the seven cut.

Slowly a man wanders into the street he's limping and drags on foot behind him. The party cleric goes over and offers to help the man as it seems he has a cut on his leg. He cast cure wounds on him and the man thanks him in turn then continues limping towards the alley where he told the cleric he lived.

He steps into the alley and tears the clothing from his body ripping and shredding his flesh literally from the bone and tossing it against the walls. I turn the music up just a bit. In a panic the two people on the ground attempt to run up and wrestle him to the ground but the once limping man seems to have gotten more agile I turn the music up just a bit. Finally the cleric casts detect magic and grasps a hint of enchantment magic before the body falls to the ground completely limp. *I make the music fade out and more regular *

The guards bring out their coroner while the party goes over their findings and discuss various theories. I slowly begin to mix the normal night song and the Seven cut one together Two of the players hear a strange hissing sound like a small flame springing to life. They turn around and the coroner is huddled over the body and one of the guards tackles his friend through a door. With a violent burst of flame, bone and body parts consumes the coroner killing him near instantly. Night music has completely gone. Players start to freak out they go back to examine the body again and this time they find out that there were no lungs nor a heart in this body. The music becomes slightly louder They go over to the two surviving guards men who tell them that the body was cold mere minutes after he'd started tearing at himself and that when the coroner cut into his chest a small flame appeared.

Armed with this knowledge the party decides to try and trace back the steps of the victim when they see a dark figure move into an alleyway. A brief chase ensues they find the cloaked figure singing to themselves in a dead end alley and quickly tackle them. They did not resist. Had a few of my friends sing the creepy song I prepared and just played it of my phone while they restrained the figure They figure out it's another walking corpse and nobody wants to open it up. They figure it's another victim of the seven cut. "Very smart" the body says as it finally stopped singing. Dagger comes down body explodes. Normal night music

Afterwards they keep trying to chase the Seven Cut. I play the same song everytime and sometimes combine it with the creepy singing is one of the bodies is near and singing.

Fast forward to a session or two ago. The seven cut has stopped killing after 2 cycles of men and women. They walk into a normal toy store to meet an informant. Seven cut music plays

All my players lose their shit.

All is quiet in the streets.
Folk are a cower'n neath their sheets.
But few souls are anxious laid in wait.
Fearing all manner of cruel darkened fates.
For their watch has started, sleep has flown.
Don't dare let them tremble alone.
For the cutter heartless cold.
Tears at young and old.
He'll come and go leave naught behind
but corpses and woe
Deep deep woe.

Seven dead another spree.
Corpses hanging from the trees.
But few souls lie anxious wide awake.
Fearing the cutter and all that's at stake.
Now dear heros run and hide.
Lie still lie silent utter no plight.
For the cutter base and vile.
Ends you with a smile.
He'll chop and slice you
Cut and dice you
Eat you up whole
Eat you whole

The song I had my friends sing for good measure.