Preheat the oven to 375°F (190°C). Place the silicone skull mold on a baking sheet and lightly grease the cavities.
Brown the ground beef in a skillet over medium-high heat for 5–6 minutes. Stir in onion and garlic, cooking for another 2–3 minutes.
Season with salt, black pepper, Worcestershire sauce, ketchup, and smoked paprika. Stir well, then let the mixture cool for 5 minutes.
Mix in shredded cheddar cheese, pickles, and jalapeños if using.
Divide pizza or bread dough into 6 equal pieces and roll each into a 5–6 inch round.
Press each round into a skull mold cavity, leaving edges hanging over. Fill with 2–3 tablespoons of beef mixture, fold the edges over, and pinch to seal.
Brush the tops with egg wash and poke a tiny vent in the center of each bun.
Bake for 20–25 minutes until golden brown. Let rest in molds for 5 minutes, then unmold and serve warm with ketchup, mustard, or chipotle mayo.