Preheat your grill or skillet over medium-high heat and season the ground beef mixture with salt and pepper, then form into four small, slightly flattened burger patties.
Cook the patties for about 4–5 minutes per side until they develop a nice char and are cooked through, filling the air with a savory aroma.
During the last minute of cooking, top each patty with a slice of cheddar cheese and let it melt until oozy and slightly bubbly.
While the cheese melts, briefly toast the hamburger buns until golden and fragrant.
Assemble each monster burger by spreading ketchup and mustard on the bottom bun, then placing the cheesy beef patty on top.
Add shredded lettuce for hair or wild monster features, then place googly eyes or black olives on the cheese for eyes.
Use additional ketchup, mustard, or cheese to create jagged monster teeth and mouths on the burger for a spooky, fun face.
Top each assembled burger with the other half of the bun, gently pressing down to secure the decorations.
Serve the monster burgers immediately with extra toppings or sides to match the spooky theme.
