In a medium bowl mix the refried beans and about 1/3 cup of the salsa together.
Pour into an 8 or 9" round glass baking dish and spread.
Spread green chilies if using.
Layer on sliced olives if using.
Cover with remaining salsa.
Cover with shredded cheese.
Bake in oven at 350 degrees for about 20 min or until heated through -- OR -- microwave on high with vented plastic wrap for about 5 minutes.
While the dip is cooking make the "spiders".
Using a toothpick poke 3 holes on opposite sides of each whole olive. (Yes I know spiders have 8 legs, not 6, but I ran out of room). Cut individual leaves off the rosemary and stick one into each hole. Then slip a raisin most of the way into the olive leaving out a small "head".
Let the dip sit for a few minutes after removing from the oven/microwave.
Spoon the sour cream into a sandwich bag and clip off the corner of the bag (make it small). Start by putting a dot of sour cream in the center of your dip, then make lines starting from the center to the edge. Make 8 lines in total (like you would cut a pie). Then, starting near the center, connect the lines creating the "web". When complete scatter your "spiders" on the web.