THE COBWEB CONFESSION CREEPY, CRAWLY CRITTERS -- YUCK!  Poor Todd. First he has to give up his room for an old friend of his father's who's visiting. Then his valuable baseball card collection is stolen. Now Mr. Merlin says the class is going to be studying spiders. Todd hates spiders.  But then Mr. Merlin tells the Third-Grade Detectives that a spider's web may help catch the thief. Maybe spiders aren't so bad after all.