If you have a giant spider web, you need a giant spider to live on it.
He's made with a body of foam and duct tape, I just broke off a few pieces of foam 2x4 and taped over them to get a somewhat oblong shape. Then painted it black, I later added a red duct tape hourglass as well.
Once the body is made you get some pipe insulation and cut V shaped chunks out of it and glue it back together to make the angles of the legs.
Shove some sticks or in my case trim into the body to make places for the legs to slide on. Slide the legs on and glue them in place if needed.
To attach the head I just used twine around the jaw of the skull. I wove the legs into the web some, and used electrical tape to further secure it in place.