Mix the refried beans with the taco seasoning packet in a bowl until evenly combined.
Spread the seasoned beans in an even layer in a shallow 8-inch serving dish.
Spoon the guacamole over the beans and smooth it into a second layer.
Use 3/4 cup of the sour cream to create the next layer, spreading it gently over the guacamole.
Sprinkle the shredded cheese evenly across the sour cream layer.
Add the diced tomatoes as the fifth layer.
Scatter the sliced black olives and chopped green onions over the tomatoes.
Place the remaining 1/4 cup sour cream in a small zip-top bag, snip a tiny corner, and pipe concentric circles on top. Drag a toothpick from the center outward in several lines to form a spiderweb. Set one olive slice in the center as a spider.