Add 1/3 cup oil to a 10x14 inch pan. Use your hands to lightly coat the pan with oil.
Then, gently transfer the dough into the center of the pan.
Carefully turn the dough to coat it in entirely in oil. Then, spread the dough out to the edges of the pan.
Use your fingers to make indentations over the surface of the dough. Cover and let the dough rise at room temperature, about 1 1/2-2 hours, until doubled in size.
Preheat the oven to 500 degrees and move a rack to the lower third of the oven.
In a small mixing bowl, toss the garlic, rosemary, sea salt, and red pepper together.
Cut half of the olives into halves for spider bodies. Cut the other half of the olives into thin strips for spider legs.
Gently press olives into dough to create spider shapes. Sprinkle garlic mixture over top of the dough.
Bake for 18-20 minutes, or until focaccia is puffy and golden brown on top.
Carefully transfer the focaccia to a wire rack to cool.
Serve while warm, or cool completely and store wrapped in foil, or portioned into freezer bags to freeze.