In 2237, Spock encountered and was nearly killed by a Le-matya, while undergoing his kahs-wan ordeal. Spock was fortunately saved by his petsehlat, I-Chaya, and his cousin, Selek, who was able to incapacitate the Le-matya with a Vulcan nerve pinch. Unfortunately, I-Chaya was injured by the Le-matya's claws and, by the time a healer arrived, was beyond meaningful aid. The healer offered Spock a choice: a treatment that would allow the creature a longer, though painful, life or to to release him from his suffering. Spock chose the latter, the most logical choice. This decision was instrumental in his embracing the Vulcan ways of his father.
In the script of "Yesteryear", the species name Le-matya is consistently underlined, like no other word in the teleplay. Also, the script states, "A Le-matya is a creature resembling a mountain lion... but it is huge, has an almost impenetrable leathery gray hide, and the poison of its claws and fangs is lethal." The creature was evidently animated with more colorful skin shades. For the Le-matya's growl, the quite famous call of Godzilla was used. (Trek Navigator: The Ultimate Guide to the Entire Trek Saga, p. 272) The novelization of "Yesteryear" (in Star Trek Log 1) is consistent with the scripted description of the Le-matya, referring to it as having a "leathery-grey hide."