Ethan, still filled with confidence and pride at making Impervius work and learning a new spell while doing it, walked over to some great mounds of dust in a corner of the room. Seeing spiders, he was immediately kindled to hatred. Deletrius seemed to be the correct spell for the occasion. Raising his wand, Ethan saw a great, big, hairy spider crawling amongst the others. "De- de- Deletrius!" he stammered to no effect. The spider seemed to have taken all the confidence of his previous victory away. Ethan started to back away, but he couldn't just leave them there for someone else to have to take care of. He was determined not to be a coward. Stepping back toward the mounds, he raised his wand, concentrated on the goal of a spider-free room and said firmly, "Deletrius!" He opened his eye just a crack, and couldn't have been happier. The spiders were gone along with the dust. He didn't care where they had gone, as long as it wasn't at Hogwarts. Hmm. Ethan vaguely remembered reading somewhere, probably in a library book, that Deletrius could also be used for the purpose of deleting the evidence of a wand's past spells. He decided to ask Professor Knox if this was true. Ethan raised his hand, and waited for a response.