chimalcoatl.

a rare snake whose body can become flat and round, like a shield (hence its name); a foolish person can see it and have an unfortunate fate; a wise person might earn the rank of eagle or jaguar (warrior), become a ruler or a general; the warrior reference seems borne out by the fact that the shield painted as a part of the snake in the Florentine Codex is one with a step-fret coil

Digital Florentine Codex/Códice Florentino Digital, edited by Kim N. Richter and Alicia Maria Houtrouw, "Book 11: Earthly Things", fol. 85r, Sahagún, Bernardino de. Florentine Codex: General History of the Things of New Spain. Transcribed and translated with notes by Arthur J. O. Anderson and Charles E. Dibble. 2nd rev. ed. Santa Fe, NM: School of American Research / University of Utah Press, 1950–82. Getty Research Institute, 2023. https://florentinecodex.getty.edu/en/book/11/folio/85r?spTexts=&nhTexts= Accessed 31 October 2025.