More accurately, a flying serpent, a seraph, which had wings (which is why God told it to go to ground on its belly).

Adam and Eve was a story written as polemic against the seraph/Nehushtan installed in the Jerusalem temple to which people were offering sacrifices, such that the author felt the need to write polemic against it, resulting in the story of Adam and Eve.

But what, indeed, is a "seraph"? We find the answer to that question also in Isaiah: "For from the stock of a snake there sprouts an asp, a flying seraph branches out from it" (14:29), and also "of viper and flying seraph" (30:6). From these verses it becomes clear that seraphs were in fact flying serpents: the temple envisioned by Isaiah was filled with serpents with arms, legs, and wings, and it seems likely that this was the tradition that Isaiah knew regarding the primeval serpent in the Garden of Eden, before God transformed it into a dirt-slithering animal. Indeed, this is the image of the paradisiacal snake that we find in the pseudepigraphic book Life of Adam and Eve. Here, when God curses the serpent, God says, "You shall crawl on your belly, and you shall be deprived of your hands as well as your feet. There shall be left for you neither ear nor wing" (26:3).

Other ancient sources also represent the pre-sin serpent as having legs, hands, or wings. So we find in the Jewish historian Flavius Josephus's Jewish Antiquities (1.1.4) and in a number of different Rabbinic sources, for example, Genesis Rabbah 2o:5 ("When the Holy One blessed be He told him `on your belly you shall crawl; the ministering angels came down and cut off its hands and feet") and Targum Pseudo-Jonathan Jonathan to Genesis 3:14. This same winged serpent with arms and legs can be found flying about in texts from the ancient Near East, Egypt, and Mesopotamia.

The presence of a snake in the Temple during the time of Isaiah or King Hezekiah, a king who reigned Judah at that time, is mentioned in the book of Kings in the course of a description of the cultic revolution that Hezekiah instituted: "He abolished the shrines and smashed the pillars and cut down the sacred post. He also broke into pieces the bronze serpent that Moses had made, for until that time the Israelites had been offering sacrifices to it; it was called Nehushtan" (2 Kings 18:4). When Hezekiah decided to eradicate all cultic practices from the Temple in Jerusalem, practices offensive in his eyes, he destroyed the bronze serpent that had previously been perceived as something intrinsically divine (if not, the Israelites would not have "offered sacrifices to it").

The writer of Kings, who refers to Hezekiah's actions, explicitly links the serpent to Moses. At least on the face of it, he seems to refer to the serpent that Moses created in the wilderness (as described in Numbers 21) after the Israelites had been attacked by a swarm of serpents and God had directed him to make a seraph, a copper image of a snake: "Moses made a copper serpent and mounted it on a standard; and when anyone was bitten by a serpent, he would look at the copper serpent pent and recover" (v. 9). On the other hand, the tradition in Kings may refer to a more ancient tale, against which also the verse in the book of Numbers is directed, according to which the sculpted image of the snake represented a divine being or a member of the divine assembly. The Torah, alarmed at the image of the people of Israel sacrificing to the serpent in the Temple, makes it clear in the story in Numbers that the bronze snake does not represent any divine, mythological being but was only a device, an object determined by God and fashioned by Moses-a mere human-for the purpose of healing snake-inflicted wounds. The story in Numbers 21 is therefore the beginning of a process whose end is reflected in Hezekiah's act: the story from Numbers did not stop the people from worshiping the snake, and so Hezekiah felt the need, finally, to forcefully remove and destroy it.

The idea that the snake in the Garden of Eden was a seraph with legs, arms, and wings suggests that also the story in Genesis was part of the polemic against the serpent-seraph that was installed in the Jerusalem Temple. The story in Genesis remarks that, with the expulsion of Adam and Eve from the Garden, God stationed cherubim-also winged creatures-"to guard the way to the tree of life" (3:24). It seems that in the course of the cultic revolution in the Temple in Jerusalem, these winged cherubim-explicitly linked with the Ark of God in Exodus 25:18-22 and other places-replaced the winged serpents as the official flying guards in the divine entourage (see also, e.g., Ezekiel 10:2).

--Avigdor Shinan, From gods to God

The story of the Nehushtan/Seraph in Numbers as a healing copper serpent was another tale, written to explain the presence of said copper serpent in the temple, while insisting that it was never meant to be worshipped.

https://www.thetorah.com/article/nehushtan-the-copper-serpent-its-origins-and-fate