Magical Creatures in Midrash
עָל בָּת בְּהָהוּא בֵּי רַבָּנַן אִידְּמִי לֵיהּ כְּתַנִּינָא דְּשִׁבְעָה רֵישְׁווֹתֵיהּ כֹּל כְּרִיעָה דִּכְרַע נְתַר חַד רֵישֵׁיהּ אֲמַר לְהוּ לִמְחַר אִי לָא אִיתְרְחִישׁ נִיסָּא סַכֵּינְתִּין
So he [R. Aha b. Ya’akov] entered and spent the night in that schoolhouse, during which it [the demon] appeared to him in the guise of a seven-headed dragon. Every time he [the R. Ya’akov] fell on his knees [in prayer] one head fell off. The next day he said to them: “Had not a miracle occurred, you would have endangered my life.”

The passage below is rare description of a Talmudic sage battling a dragon, unsurprisingly, the sage relies on prayer rather than physical strength to defeat the monster.

The passage below is a technical discussion concerning iconography (the Talmudic sages strongly disapproved of the folk use of dragon imagery and other mythical and magical icons found in Ancient Israel and the neighbouring cultures).

תנו רבנן איזהו צורת דרקון פירש רשב"א כל שיש לו ציצין בין פרקיו מחוי רבי אסי בין פרקי צואר אמר ר' חמא ברבי חנינא הלכה כר"ש בן אלעזר
§ The Sages taught: What is a figure of a dragon? Rabbi Shimon ben Elazar explained: It is any figure that has scales between its joints. Rabbi Asi motioned with his hands to depict scales between the joints of the neck. Rabbi Ḥama, son of Rabbi Ḥanina, says: The halakha is in accordance with the opinion of Rabbi Shimon ben Elazar.

Note: The verse in the passage below is translated in some bibles as "Sea Monsters" rather than dragons.

והקב"ה קרא אל ירמיה ואמר לו, גם תנין חלצו שד הניקו גוריהן וגו' (איכה ד ג), התנין הזה כשהוא בא לינק את אמו, היא רואה אותו מרחוק וחולצת שדיה בשביל שיינק, ולא יראה שדיה מכוסין, ואינו יונק, ובני לא עשו כן, אלא כשראו אותי נכנס לבית, בא נשה והכניס שם את הצלם כדי להוציאני מתוכו, [בתחלה עשו לו פרצוף אחד והעמידו למערב כביכול היתה השכינה הולכת לזויות אחרת מקום שלא נראה הפסל כשראה מנשה כך עשה לו ד' פרצופין שיראה השכינה ויסתלק.

Then the Holy One called unto Jeremiah and said to him (in Lam. 4:3): EVEN DRAGONS EXTEND A BREAST TO NURSE THEIR YOUNG; < THE DAUGHTER OF MY PEOPLE HAS BECOME CRUEL >. When the dragon (tannin) comes to nurse from its mother, she sees it from afar and extends her breasts for it to nurse; for it would not see her breasts, < if > covered, and would not nurse. Now my children do not act like this. Instead, when they saw me entering the house, Manasseh came and brought in the image in order to force me out of it. [At first they made a single face, and set it up to the west. The Divine Presence went, as it were, to another corner, a place where the image would not be seen. When Manasseh saw that, he made four faces so that the Divine Presence would see them and depart.

The midrashic source for the legend below is not listed in the original text.

On still another occasion Nebuchadnezzar tried to persuade Daniel to worship an idol, this time a dragon that devoured all who approached it, and therefore was adored as a god by the Babylonians. Daniel had straw mixed with nails fed to him, and the dragon ate and perished almost immediately.

See also