Horned Serpent is one of the four houses of Ilvermorny School of Witchcraft and Wizardry. The name was chosen by Isolt Sayre. Thunderbird house stands for the mind of the wizard and is the house for scholars.
The Horned Serpent is a magical creature from the legends of the native peoples of North America, particularly the southwest and the southeast. The description of the Horned Serpent which Isolt encountered matches that of the Muscogee people of southeastern woodlands.
From the Web
Horned Serpent in Native American Cultures on Wikipedia