הנה יצא המימה. לִנְקָבָיו; שֶׁהָיָה עוֹשֶׂה עַצְמוֹ אֱלוֹהַּ וְאוֹמֵר שֶׁאֵינוֹ צָרִיךְ לִנְקָבָיו, וּמַשְׁכִּים וְיוֹצֵא לַנִּילוּס וְעוֹשֶׂה שָׁם צְרָכָיו (תנחומא):

הנה יצא המימה LO, HE GOETH OUT UNTO THE WATER to ease himself. For he claimed to be a god and asserted that because of his divine power he did not need to ease himself; and therefore he used to rise early and go to the Nile and there eased himself in secret (Midrash Tanchuma, Vaera 14; Exodus Rabbah 9:8).