Trapdoor spiders are big spiders living in burrow, hidden behind door constructed out of available material. Any unfortunate critter wandering too close will be ambushed and eaten. I made a specific kind, called ravine trapdoor spider ( Cyclocosmia truncata ) whose rear end of their abdomen is flat, hardened, and has interesting pattern. Like many big spiders, they are vulnerable to parasitic wasps. Upon burrow invasion, they position themselves so that their hardened end faces the invader. Apparently it's tough enough to protect against sting. Source: Britannica .
Notes about origami design and fold