Whisk together the ketchup, brown sugar, barbecue sauce, Worcestershire sauce, Dijon mustard, liquid smoke, salt, garlic powder, and pepper to make the marinade.
Nestle the pork shoulder tightly inside the Crockpot and pour the marinade over it, squeezing some underneath so all sides of the meat are coated.
Cover and cook on HIGH for 4-5 hours or LOW for 8-10 hours, until the meat falls apart easily.
Shred the meat with two forks and mix it into the juices. Serve as is, or on potato rolls or brioche buns with coleslaw.