So I thought I'd show you a couple huge spiders I've made with the kids in the past. I first drew a big circle on black butcher paper and cut out two. Then I drew a big oval-ish/teardrop shape on the black paper and again cut out two. I stapled the circles together and the ovals together and left an opening on both of the them. The kids then stuffed them both with crumpled up paper. Once they seemed puffy enough, I closed up the openings with more staples, and then stapled the circle to the oval. Can you see a spider in your head yet? Then the kids glued on some eyes made from red craft foam and we added some pedipalps that are beside the mouth with extra thick pipe cleaners. Then I hung the entire thing up from the ceiling in the corner of the room. I added the legs after it was up there. They were made out of black crepe paper, stapled in certain spots to make knees and "ankles." OK, I'll show you now.
Fun Fact: Spiders actually have 48 knees! They have 6 joints on each of their 8 legs.