"Take your staff and cast it down before Pharaoh." The Holy One, blessed be He, said: This wicked one exalts himself and called himself a crocodile, as it is written, "the great crocodile" (Ezekiel 29:3). Go and say to him: See this staff. It is dry wood, and it becomes a crocodile and has breath and a spirit in it, and it swallows all the staffs, and in the end it returns to dry wood. So too you: I created you from a putrid drop and gave you kingship, and you exalt yourself and say, "The Nile is mine and I made myself," and behold I am returning you to chaos and void. You swallowed all the staffs of the tribes of Israel; behold I am bringing out what you swallowed from your mouth. You forgot what happened to your ancestor, "and the LORD afflicted Pharaoh" (Genesis 12:17); so too I am bringing upon you ten afflictions for the sake of Israel. When Moses and Aaron came and stood before Pharaoh, they saw that they resembled the ministering angels: their stature like the cedars of Lebanon, the pupils of their eyes like the orbs of the sun, their beards like clusters of dates, the radiance of their faces like the radiance of the sun, the staff of God in their hand on which the Explicit Name was engraved, and the speech of their mouths like a flame of fire. Immediately dread fell upon them. Now there were four hundred gates to Pharaoh's palace, and at each and every gate were lions and bears and savage beasts, and no creature could enter there until they were fed meat so that they would not harm him. When Moses and Aaron came, they all gathered and surrounded them and licked their feet and began to escort them until they came before Pharaoh. And all the kings of east and west, when they saw them, dread fell upon them, and trembling and shuddering and terror seized Pharaoh and all who sat before him, and they removed their crowns from their heads and bowed down to them. At that moment Pharaoh needed to relieve himself and entered the privy, and twelve mice came to him and bit him on every side of his seat, and he cried out a great and bitter cry until the nobles of the kingdom heard the sound of his cry. Afterward he returned and sat upon his throne and his heart grew strong. He said to Moses and Aaron: Who are you, and from where have you come, and who sent you to me? They said to him: "The God of the Hebrews has sent me to you, saying, Let My people go that they may serve Me." Immediately he said, "I do not know the LORD" (Exodus 5:2); he never sent me a letter of peace and never brought me a gift.
God Rebukes Pharaoh the Crocodile and the Awesome Entrance of Moses
Yalkut Shimoni on Torah 181:4
קַח אֶת מַטְּךָ וְהַשְׁלֵךְ לִפְנֵי פַרְעֹה. אָמַר הַקָּדוֹשׁ בָּרוּךְ הוּא, רָשָׁע זֶה מִתְגָּאֶה וְקָרָא עַצְמוֹ תַּנִּין, דִּכְתִיב (יחזקאל כט, ג) "הַתַּנִּים הַגָּדוֹל", לֵךְ וֶאֱמֹר לוֹ רְאֵה מַטֶּה זֶה. הוּא עֵץ יָבֵשׁ, וְנַעֲשֶׂה תַנִּין, וְיֵשׁ בּוֹ רוּחַ וּנְשָׁמָה, וְהוּא בוֹלֵעַ כָּל הַמַּטּוֹת, וְסוֹפוֹ לַחֲזֹר עֵץ יָבֵשׁ. אַף אַתָּה, בָּרָאתִי אוֹתְךָ מִטִּפָּה סְרוּחָה וְנָתַתִּי לְךָ מְלוּכָה וְנִתְגָּאֶה אַתָּה וְאָמַרְתָּ "לִי יְאֹרִי וַאֲנִי עֲשִׂיתִנִי", הֲרֵינִי מַחֲזִירְךָ לְתֹהוּ וָבֹהוּ. אַתָּה בָּלַעְתָּ כָּל מַטּוֹת שִׁבְטֵי יִשְׂרָאֵל, הֲרֵינִי מוֹצִיא בִלְעֲךָ מִפִּיךָ, שָׁכַחְתָּ מָה קָרָה לִזְקֵנְךָ (בראשית יב, יז) "וַיְנַגַּע ה' אֶת פַּרְעֹה", אַף אֲנִי מֵבִיא עָלֶיךָ עֶשֶׂר נְגָעִים בִּשְׁבִיל יִשְׂרָאֵל. כְּשֶׁבָּאוּ מֹשֶׁה וְאַהֲרֹן, עָמְדוּ לִפְנֵי פַרְעֹה, וְהָיוּ רוֹאִין שֶׁהֵם דּוֹמִים לְמַלְאֲכֵי הַשָּׁרֵת, וְרוּם קוֹמָתָן כְּאַרְזֵי לְבָנוֹן, וְגַלְגַּלֵּי עֵינֵיהֶם דּוֹמִים לְגַלְגַּלֵּי חַמָּה, וּזְקָנוֹת שֶׁלָּהֶם כְּאֶשְׁכְּלוֹת תְּמָרָה, וְזִיו פְּנֵיהֶם כְּזִיו הַחַמָּה, וּמַטֵּה הָאֱלֹהִים בְּיָדָם שֶׁחָקוּק עָלָיו שֵׁם הַמְּפֹרָשׁ, וְדִבּוּר פִּיהֶם כְּאֵשׁ שַׁלְהֶבֶת, מִיָּד נָפַל פַּחְדָּם עֲלֵיהֶם. וְהָיוּ אַרְבַּע מֵאוֹת פְּתָחִים לְפַלְטְרִים שֶׁל פַּרְעֹה, וְעַל כָּל פֶּתַח וּפֶתַח אֲרָיוֹת וְדֻבִּים וְחַיּוֹת רָעוֹת, וְלֹא הָיְתָה בְּרִיָּה יְכוֹלָה לִכָּנֵס שָׁם עַד שֶׁהָיוּ מַאֲכִילִין אוֹתָם בָּשָׂר שֶׁלֹּא יְהוּ מַזִּיקִין אוֹתוֹ, וּכְשֶׁבָּאוּ מֹשֶׁה וְאַהֲרֹן נִתְקַבְּצוּ כֻּלָּם וְסוֹבְבִים וּמְלַחֲכִין רַגְלֵיהֶם וְהִתְחִילוּ לְלַוֹּתָם עַד שֶׁבָּאוּ לִפְנֵי פַּרְעֹה. וְכָל מַלְכֵי מִזְרָח וּמַעֲרָב כְּשֶׁרָאוּ אוֹתָם נָפַל פַּחְדָּם עֲלֵיהֶם, וְזִיעַ וְרֶתֶת וְחַלְחָלָה אָחַז לְפַרְעֹה וּלְכָל הַיּוֹשְׁבִים לְפָנָיו, וְהֵסִירוּ כִּתְרֵיהֶם מֵעַל רָאשֵׁיהֶם וְהִשְׁתַּחֲווּ לָהֶם. בְּאוֹתָהּ שָׁעָה הֻצְרָךְ פַּרְעֹה לִנְקָבָיו וְנִכְנַס לְבֵית הַכִּסֵּא, וְנִזְדַּמְּנוּ לוֹ שְׁנֵים עָשָׂר עַכְבָּרִים וְהָיוּ נוֹשְׁכִים אוֹתוֹ בְּכָל צַד מוֹשָׁבוֹ, וְצָעַק צְעָקָה גְּדוֹלָה וּמָרָה עַד שֶׁשָּׁמְעוּ קוֹל צַעֲקָתוֹ גְּדוֹלֵי הַמַּלְכוּת. וְאַחַר כָּךְ חָזַר וְיָשַׁב עַל כִּסְאוֹ וְנִתְחַזֵּק לִבּוֹ, אָמַר לְמֹשֶׁה וְאַהֲרֹן, מִי אַתֶּם וּמֵאַיִן בָּאתֶם וּמִי שִׁגֶּרְכֶם אֶצְלִי, אָמְרוּ לוֹ, "אֱלֹהֵי הָעִבְרִים שְׁלָחַנִי אֵלֶיךָ [לאמר] שַׁלַּח אֶת עַמִּי וְיַעַבְדֻנִי", מִיָּד אָמַר (שמות ה, ב) "לֹא יָדַעְתִּי אֶת ה'", מֵעוֹלָם לֹא שָׁלַח לִי אִגֶּרֶת שָׁלוֹם וְלֹא הֵבִיא לִי דּוֹרוֹן.