You could experiment with food coloring to see if you can get the ketchup a more blood color (probably adding a bit of blue would help) and it wouldn't change the flavor.
I'd suggest doing chili/jelly meatballs too, as those can look pretty gross too with the right label - could add some red food coloring to see if you can get the sauce to look more bloody, but it still looks pretty good and frankly if you call them something in theme (like freshly ground human meatballs or something) then they'll still gross everyone out (until they eat them - they are super easy and tasty!)
http://funnyisfamily.com/2014/09/crock-pot-grape-jelly-meatballs.html
Decent instructions, but I just throw everything in the crockpot and cook a minimum of 2 hours on low before the party starts. They never last the night.
I'd suggest doing chili/jelly meatballs too, as those can look pretty gross too with the right label - could add some red food coloring to see if you can get the sauce to look more bloody, but it still looks pretty good and frankly if you call them something in theme (like freshly ground human meatballs or something) then they'll still gross everyone out (until they eat them - they are super easy and tasty!)
http://funnyisfamily.com/2014/09/crock-pot-grape-jelly-meatballs.html
Decent instructions, but I just throw everything in the crockpot and cook a minimum of 2 hours on low before the party starts. They never last the night.
