Form the beef into 4 burger patties 1/2 inch smaller in diameter than your buns. Generously season both sides with salt and pepper and grill, turning once, until cooked through, about 10 minutes.
While the burgers grill, press the bottom halves of the buns very flat and cut into 1/2-inch-wide strips. Cut the pickles into smiles, frowns, or angry mouths.
During the last minute of grilling, top each patty with a slice of cheese, letting it hang over the sides. When the cheese melts, transfer the patties to the top halves of the buns. Quickly arrange the bottom bun strips on top to resemble mummy bandages, leaving a space for eyes, and pressing the strips against the cheese. Make “eyes” with ketchup and place the pickle “mouths” on top.