Spread the refried beans evenly across the bottom of a shallow serving dish or pie plate.
Stir 1 cup of the sour cream with the taco seasoning until smooth. Spread this mixture over the beans.
Spoon the guacamole over the sour cream layer and spread it gently to cover.
Sprinkle the shredded cheddar cheese evenly on top of the guacamole.
Add the diced tomatoes as the next layer.
Place the remaining 1/2 cup sour cream in a small zip-top bag, snip off one corner, and pipe concentric circles on top. Drag a knife from the center outward in several spots to form the web design.
Place black olive slices on the web to look like spiders. Serve with tortilla chips.