The sinew of the thigh of a koy is forbidden. The Merciful One made it depend on the socket of the thigh, and this creature indeed has a socket. Its blood: from where? From "any blood you shall not eat" (Leviticus 7:26). A verse was required to forbid the doubtful case, since one holds that a koy is a creature in its own right. Its forbidden fat: from where? From "any fat" (Leviticus 7:23). Its carrion status: from where? From "any carcass" (Leviticus 7:24, or Leviticus 17:15).
The Sinew of the Koy and the Doubtful Creature
Yalkut Shimoni on Torah 133:9
גִּיד הַנָּשֶׁה שֶׁל כְּוִי אָסוּר, בְּכַף הַיָּרֵךְ תָּלָה רַחְמָנָא וְהָא אִית לֵיהּ כַּף דָּמוֹ [מִנַּיִן] (ויקרא ז, כו) מִ"כָל דָּם לֹא תֹאכְלוּ" אִצְטְרִיךְ קְרָא לְמֵיסַר סְפֵיקָא קַסָּבַר כְּוִי בְּרִיָּה בִּפְנֵי עַצְמָהּ הִיא חֶלְבּוֹ מִנַּיִן (שם כג) מִ"כָּל חֵלֶב". נִבְלָתוֹ מִנַּיִן (ויקרא יד, כא) מִ"כָל נְבֵלָה".