mazacoatl.

Headword: 
mazacoatl.
Principal English Translation: 

a fat worm with horns, or a snake that does no harm (see Molina)

IPAspelling: 
mɑsɑːkoːɑːtɬ
Alonso de Molina: 

mazacoatl. gusano gordo con cuernos, o culebra grande que no haze mal.
Alonso de Molina, Vocabulario en lengua castellana y mexicana y mexicana y castellana, 1571, part 2, Nahuatl to Spanish, f. 50r. col. 1. Thanks to Joe Campbell for providing the transcription.

Frances Karttunen: 

MAZĀCŌĀ-TL pl: -MEH a type of horned caterpillar or a type of large, nonvenomous snake, a boa / gusano gordo con cuernos o culebra grande que no hace mal (M), culebra mazacuate (Z) [(2)Zp. 37, 166, (3)Xp. 52]. Several Spanish sources remark that the snake of this name is large enough to feed on four-legged animals. The literal sense of the name ‘deer snake’ probably refers to its alleged diet rather than to any aspect of its appearance. The caterpillar, on the other hand, takes its names from its antler-like projections. See MAZĀ-TL, CŌĀ-TL.
Frances Karttunen, An Analytical Dictionary of Nahuatl (Norman: University of Oklahoma Press, 1992), 142.

Attestations from sources in English: 

mazacoatl (mazacooatl, mazacoooatl) = a snake that is named for its deer-like appearance (with horns); it could be tamed and bred for its flesh/meat; sometimes with or without rattles, it seems to come in different varieties as described in the Florentine Codex, Book 11, folio 82v-83r.
Digital Florentine Codex/Códice Florentino Digital, edited by Kim N. Richter and Alicia Maria Houtrouw, "Book 11: Earthly Things", fol. 82v, 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/82v Accessed 31 October 2025.

themes: 
Animals, Bugs, Insects, Reptiles, Fish, etc.
Snakes, Serpents