Satan as a Dragon

Why is Satan depicted as a dragon in Revelation, and a multi-headed one?

Revelation 12:9 calls Satan δράκων (drakon, dragon) and ὄφις (ophis, snake), the later being used in Genesis 3 LXX.

Revelation 12:3 says he has 7 heads, and this may refer to the apocalyptic heads of δράκων of Psalm 74:13 LXX and the “heads of Leviathan” of 74:14. The NET Bible footnote explains the origin of this imagery: “The imagery of vv. 13-14 originates in West Semitic [Ugaritic] mythology” which had a 7-headed leviathan chaos dragon.

Thus Revelation is harking back to Genesis 3 LXX ὄφις and to the West Semitic “heads of δράκων” imagery of Psalm 74:13, 14.^[1]

Lastly, one scholar stated:

“Dragon” (δράκων) is another OT word for the evil sea monster that symbolizes evil kingdoms who oppress Israel. Often the wicked kingdom of Egypt is portrayed by this emblem.^[2]

Thus, it is a familiar sight, and even reminds one of the legend of Hercules battling the multi-headed Hydra.

Footnotes:
^[1] In Romans 16:20 Paul says that God will “crush” (συντρίβω; suntribo) Satan under your feet, and the same word is used in Psalm 74:13-14 LXX [LXX 73:13-14]: “You crushed (συντρίβω; suntribo) the heads of the dragons.(δρακόντων; drakónton) on the waters; ⁽¹⁴⁾ you shattered (συνθλάω; synthláō) the heads of the dragon (δράκων).” But feet only appear in Genesis 3:15, with a foot crushing the head of the serpent. Thus, Paul is taking the foot of Genesis 3:15 and συντρίβω of Psalm 74:13 LXX and putting them together into one eschatological action. (7/26/2022)
^[2] Gregory Beale, The Book of Revelation (The New International Greek Testament Commentary) (Grand Rapids, MI: Eerdmans Publishing Co., 1999), 632.