Diy Giant Spider Halloween Decoration Outdoor . Add them into bushes, trees or anywhere in your yard for a spooky effect. Using your foam brush and brown acrylic paint, paint your styrofoam balls. The Build of a Giant Spider Giant spider, Halloween diy outdoor from www.pinterest.com There is just something unsettling about the sight of a coffin in outside decorations. Diy halloween crafts halloween halloween decoration ideas. Bend each leg upward about 3 inches away from the board, then downward in 2 more spots to make the shape of the spider’s leg.