Preheat your grill or grill pan over medium-high heat until hot, and lightly oil the grates.
In a mixing bowl, gently combine the ground beef with salt and black pepper, mixing just until evenly seasoned—avoid overworking to keep the burgers tender.
Divide the beef mixture into four equal portions and shape each into a thick, slightly flattened patty, about ¾ inch thick, with some edges for a rustic look.
Place the patties on the preheated grill, cooking for about 4-5 minutes per side, until they develop a nice char and are cooked through with an internal temperature of 160°F. The exterior should be beautifully browned and slightly crispy.
During the last minute of cooking, lay slices of cheddar cheese over each burger so they melt slightly from the heat.
While the burgers are grilling, lightly toast the burger buns on the grill for about 1-2 minutes until golden and slightly crispy, then remove and set aside.
Arrange the toppings—sliced bell peppers, olives, cherry tomatoes, and shredded lettuce—next to your workspace so you can assemble monster faces easily.
Place each cooked burger on the bottom half of a bun, then decorate with colorful toppings to create wild, monster-like features—using slices of peppers, olives for eyes, and cherry tomatoes for mouths.
Fix the “eyeballs” by attaching small cheese balls or candy eyes onto the toppings with a dab of ketchup or mayo to secure them in place.
Spread ketchup and mayo on the top halves of the buns, then cap the monsters with the top buns, pressing gently to secure the toppings.
Serve the monster burgers immediately, with extra toppings on the side for additional decoration if desired, making sure each burger is a fun, chaotic art piece ready to enjoy.
