How did Hashem judge the Egyptian deities?

Summary: Idols melting, judges judged, or national guardian angels getting their comeuppance.

Post: In Masei we read that Hashem had executed judgement against the Egyptian deities.

ד  וּמִצְרַיִם מְקַבְּרִים, אֵת אֲשֶׁר הִכָּה ה בָּהֶם--כָּל-בְּכוֹר; וּבֵאלֹהֵיהֶם, עָשָׂה ה שְׁפָטִים.

4 while the Egyptians were burying them that the LORD had smitten among them, even all their first-born; upon their gods also the LORD executed judgments.

These masaot, in general, form a brief summary of previous events, mentioned in greater detail elsewhere. But while we know of the punishment of the Egyptian firstborn, as the Torah tells us, where is the executed judgement against the Egyptian gods?

Ibn Ezra writes:

ובאלהיהם עשה ה' שפטים -כמו ראש דגון, כי כן אמר השם למשה:

"Like the head of Dagon, for so did Hashem say to Moshe."

The reference is to Shmuel Aleph, 5:3, when the Philistines capture the ark:

ג  וַיַּשְׁכִּמוּ אַשְׁדּוֹדִים, מִמָּחֳרָת, וְהִנֵּה דָגוֹן נֹפֵל לְפָנָיו אַרְצָה, לִפְנֵי אֲרוֹן ה; וַיִּקְחוּ, אֶת-דָּגוֹן, וַיָּשִׁבוּ אֹתוֹ, לִמְקוֹמוֹ.	3 And when they of Ashdod arose early on the morrow, behold, Dagon was fallen upon his face to the ground before the ark of the LORD. And they took Dagon, and set him in his place again.
ד  וַיַּשְׁכִּמוּ בַבֹּקֶר, מִמָּחֳרָת, וְהִנֵּה דָגוֹן נֹפֵל לְפָנָיו אַרְצָה, לִפְנֵי אֲרוֹן ה; וְרֹאשׁ דָּגוֹן וּשְׁתֵּי כַּפּוֹת יָדָיו, כְּרֻתוֹת אֶל-הַמִּפְתָּן--רַק דָּגוֹן, נִשְׁאַר עָלָיו.	4 And when they arose early on the morrow morning, behold, Dagon was fallen upon his face to the ground before the ark of the LORD; and the head of Dagon and both the palms of his hands lay cut off upon the threshold; only the trunk of Dagon was left to him.

This is punishment for taking the aron. Ibn Ezra is assuming a similar 'punishment' to the Egyptian deities. Now, nowhere is the specifics of the punishment of Egyptian deities explicitly mentioned. But Ibn Ezra agrees that they occurred, for they are described here as having happened, and Hashem had told Moshe that this would happen. In Shemot 12:12:

יב  וְעָבַרְתִּי בְאֶרֶץ-מִצְרַיִם, בַּלַּיְלָה הַזֶּה, וְהִכֵּיתִי כָל-בְּכוֹר בְּאֶרֶץ מִצְרַיִם, מֵאָדָם וְעַד-בְּהֵמָה; וּבְכָל-אֱלֹהֵי מִצְרַיִם אֶעֱשֶׂה שְׁפָטִים, אֲנִי ה.

12 For I will go through the land of Egypt in that night, and will smite all the first-born in the land of Egypt, both man and beast; and against all the gods of Egypt I will execute judgments: I am the LORD.

If Hashem promised it, then it must have happened.

I've seen some try to read the ten plagues as these punishments, each targetting specific Egyptian deities. But this is twice (in Shemot and in Bemidbar) associated specifically with the Plague of the Firstborn, not the plagues in general.

Ibn Caspi echoes Ibn Ezra:

So too Targum Yonasan, which adds details:

And the Mizraee buried those whom the Lord had killed among them, even all the first‑born; and upon their idols did the Word of the Lord do judgments; their molten idols were dissolved, their idols of stone were mutilated, their idols of earthenware broken in pieces, their wooden idols turned to ashes, and their cattle gods were slain with death.

While possible, it strikes me as way too midrashic. For their part Ibn Caspi and Ibn Ezra are pashtanim, but the Torah describes something as having happened, and they are willing to take an open canon approach.

I am tempted to see a poetic echo here. We know from Mishpatim that Elohim can mean judges. Executing judgement against the judges resonates well. And it fits in with the idea of the firstborn being generally prominent folk. Not only they were killed, but their rulers / judges would be judged on that night.

Looking around, I see that this idea is put forth by the Baalei Tosafot:

Yet Biblical scholars question that identification in Mishpatim. And there seems to be a more straightforward explanation, though of course all of this is subjective.

Chazal say that the downfall of a nation is preceded by the downfall of its sar.  (See e.g.Vayikra Rabba for a version of Yaakov's dream, with the ascending and descending of various angels.) So perhaps what is not meant is a lifeless idol, but the guardian angel(s) of the nation of Egypt. Thus, the war / punishment against Egypt is wages down below but simultaneously On High.

Indeed, the idea of 70 "bnei Elohim", perhaps corresponding to the 70 nations, might be Biblical. There is the pasuk in Haazinu:

ח בְּהַנְחֵל עֶלְיוֹן גּוֹיִם, {ס} בְּהַפְרִידוֹ בְּנֵי אָדָם; {ר} יַצֵּב גְּבֻלֹת עַמִּים, {ס} לְמִסְפַּר בְּנֵי יִשְׂרָאֵל. {ר}

8 When the Most High gave to the nations their inheritance, when He separated the children of men, He set the borders of the peoples according to the number of the children of Israel.

where the Septuagint appears to reflect an original text lemispar bnei Elohim; and the Dead Sea Scrolls, though extremely fragmentary here, seem to support such a reading as well. Thus, borders apportioned to various angels might well have Biblical precedent. And there is support for this idea in Ugaritic texts, as well.

The Zohar explores a number of these options. See inside, in chelek 2, daf 18a.