Quote from : Opal Summerfield and The Battle of Fallmoon Gap Book

Let me see,” Opal said. She quickly slurped up the rest of her lunch and then took the collar. She examined it very closely. Sure enough, she could see bits of evergreen fur pinched along the buckle strap. As she looked closer, she noticed something else. Several pieces of black onyx were sewn into the back of the collar, and they started glowing. “Well look at that,” Jack said. “Somebody’s put a spider in this biscuit.