Mary tried to concentrate on the excuses Demetrius was making as he was going on and on in circles, but she was distracted when a small spider suddenly dropped from the ceiling on a thread of web. He hung there in the air for a moment, swinging back and forth just over Demetrius’ left shoulder. Demetrius continued to explain himself. Mary, rolling her eyes, half listening because she didn't believe him, as she watched the spider fasten one end of his thread to the door frame and set off once again through the air, beginning to build his web.
What is the SYMBOL in this story?