1Start with a very large round serving dish. Spread the beans to make a level circle, leaving about a 1 1/2 inch clear outer margin.
2Spread a thin layer of plain, unsweetened yogurt on top of the beans.
(Hint: Plain, unsweetened yogurt tastes so much better than sour cream on many Mexican style dishes, and of course is healthier. Stir it well before using.)
3Make the guacamole. Juice 1 lime into a large non-metal bowl. Add peeled & pitted avacados. The lime juice will help keep them from turning brown (oxidizing.) Mash up and add seasonings, salt & pepper to taste. Heap the guacamole on top of the yogurt layer & smooth out.
4Around the empty ring at the edge, add shredded cabbage or lettuce, shredded cheese, tomato, green onion & chopped black olive.
5*Read step 7 first!
Fill a ziplock bag with about 1/2 cup plain yogurt (or sour cream), cut the tip off one end, and then use it to draw the spider web. Make 4 concentric circles (inside each other) on top of the guacamole. Put the yogurt down, take a spatula or knife, and draw lines, starting from the center outward, like spokes on a wheel. It will pull the yogurt with it, giving it a draped spider web look.
6Make a spider out of black olives for the center. Use one for the body, and cut another lengthwise to make 8 legs.
7If you are going to be storing before serving, you may spread a little extra lime juice over the top of the guacamole, before drawing the spider web on.