Preheat oven to 375. Line a baking sheet with aluminum foil.
Cut the onion in half vertically (from stem to root). Cut off stem end so the onion can be peeled. Discard the skin and tough outside layer. Carefully peel off the next layer and cut layer into quarters. Set aside the two quarters that are the most “square” to use for eyes.
Chop the rest of the onion into 1/2 inch by 1/4 inch rectangles. Set aside 8 to use for teeth; the rest will go into the meatloaf (chop these smaller if desired).
In small bowl, beat egg and stir in milk.
In large mixing bowl, combine egg mixture with ground beef, remaining onions, bread crumbs, and spices. Use hands to mix thoroughly.
Shaping
Now for the fun part! Using hands, plop meatloaf onto baking sheet. Sculpt into a head shape.
Cut strips of bacon in half, creating 8 short strips.
Use 4 pieces to wrap the circumference of the head. Lay 5th piece of bacon horizontally across the middle of the face. Above this strip, set the onion eyes; below this strip, place the onion teeth in two rows.
Place 6th strip of bacon diagonally across face, covering where the nose would be. Wrap the 7th and 8th pieces above the eyes and below the teeth.
Baking
Bake for 40 minutes or until bacon starts to crisp. If desired, garnish with ketchup blood.