I happen to be uniquely placed to divulge two of the spookiest mysteries in the American pantry. Namely: "What's in that hot mystery meat you used to be able to buy at roadside stands throughout the summer - you know, that sloppy-Joe-like, barbecue stuff?" And: "What's in that cold mystery meat that used to turn up, now and then, in the meat department at your friendly local supermarket? - you know, that pinkish-gray bread spread?"
How do I know these secrets? Two different connections. First - I have relatives who used to be in the summer roadside-stand hot mystery-meat business, and their recipe has been passed down to me. Second - I once had a job in your friendly local supermarket's meat department, where I learned that recipe as well. Prepare yourself for enlightenment.
HOT MYSTERY MEAT: Combine a mess of ground beef, ketchup, chili powder, and reconstituted dried onions in a large pot. Cook until cooked. The beef need only be browned & drained ahead of time if you choose to worry about fat calories and such things. If you're going to be serving it at a roadside stand, don't bother - other people's arteries! Anyway, use an ice-cream scoop to measure servings onto cheap, storebought buns on a paper plate, perhaps with a side of "baked" (i.e. canned, heated on the stovetop) beans and a slice of dill pickle.
COLD MYSTERY MEAT: This recipe works best when your icebox is stuffed with packages of wieners, franks, lunch meat, and other processed-meat products that say "fully cooked" on their label. Round up the ones, regardless of type, that are at or near their "best by" date. Run them through a meat grinder. Mix them thoroughly with a reasonable amount of white salad dressing, sweet pickle relish, and powdered gelatin (cherry-flavored). Press the resulting grayish-pink mush into clear plastic tubs and label them in a way that encourages people to consume it quickly. For example, in a grocery-store context, the label could say: "BUY ONE, GET ONE FREE!"