俱舍論疏 17.180

17.180

論「然大德說至如聰慧馬」，述異說也。聰慧馬者，如說有馬，人欲取其種，遂染其母。色異於常，令其行欲。後知是母，斷勢而永死。

On the Śāstra's statement, 'However, the Venerable (bhadanta) says... like the intelligent horse': This relates a differing view. Regarding the intelligent horse: as the story goes, there was a horse whose owner wished to breed it, so he dyed its mother's coat to look different from usual and made it mate with her. Afterwards, upon realizing it was its mother, it bit off its own genitals and died forever.