Spread the refried beans evenly across the bottom of a 12-inch pie plate. Use the back of a spoon or a spatula to form a smooth, uniform layer that will serve as the foundation of the dip.
Place the softened cream cheese in a medium mixing bowl and beat it with a hand mixer until completely smooth.
Add 1 1/2 cups of sour cream along with the taco seasoning. Continue mixing until the ingredients are thoroughly combined and the texture is creamy.
Carefully distribute the seasoned cream cheese mixture over the refried beans, spreading it all the way across the surface so the bean layer is fully covered.
Spoon the prepared guacamole over the creamy taco layer.
Using a spoon or offset spatula, gently smooth the guacamole into an even layer without disturbing the mixture underneath.
In a small bowl, stir together 1/4 cup sour cream and 1 tablespoon milk or water until the mixture becomes thin enough to pipe while still holding its shape.
Transfer the thinned sour cream to a piping bag, squeeze bottle, or zip-top bag with a small corner removed.
Lightly mark the desired spiderweb pattern in the guacamole using a paring knife. Pipe the sour cream directly over the traced lines to produce the spiderweb design.
Sprinkle the shredded cheddar or Mexican cheese blend around the outer edge of the pie plate, forming a border while keeping the spiderweb visible.
Add the chopped tomatoes, black olive slices, and fresh cilantro. Finish with the desired amount of sliced jalapeños, shredded iceberg lettuce, chopped green onions, and diced red or orange bell pepper.
For a Halloween presentation, place a clean decorative plastic spider over the finished spiderweb.
Serve the dip with tortilla chips. It may be served immediately or refrigerated for approximately 30 minutes beforehand so the layers can firm slightly and the flavors can blend.