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Isolt Sayre befriended a Horned Serpent when she went to a creek by Mount Greylock in the 17th century. Isolt and the Horned Serpent could understand each other which scared William the Pukwudgie. It kept telling her the same thing - "UntilI am part of your family, your family is doomed." The cryptic message concerned Isolt because she had no family at the moment and she began to think she was imagining hearing it say things. However, Isolt still visited the serpent over the years because of their strange, shared kinship and when she and her eventual family were thinking of names for houses for Ilvermorny School of Witchcraft and Wizardry she named her house "Horned Serpent" in honour of it. Shortly after, Isolt recieved a dream the evening before Chadwick Boot's eleventh birthday. She had promised him a wand but she did not know what to use as a core. She went to the creek in the dream where the Horned Serpent rose up out the water and let her take a shard of its horn. When she woke and went to the creek, she received a horn the same as she had in her dream. She then made a wand with the core as a core set in prickly ashwood, subsequently repeating the process with Chadwick's brother Webster's wand core. This would prove the fulfilment of the serpent's prophecy, as these wands later warned Chadwick and Webster of the approach of Gormlaith Gaunt.