Concerning the “Serpent” in Genesis 3 and what Eve observed and her obsession and obedience to same,

Those who serve Satan are his “seed” or offspring (Genesis 3:15), they are his children, this includes fallen angels (demons) and the rebellious of humanity; that is, those angels who allied with Satan in the Great Kingdom War and those who ally with Satan within the Realm of Time through their rejection of Elohim’s will (John 6:29; John 8:44).

Satan was NEVER a literal serpent but the Holy Spirit uses the serpent as a metaphor for Satan in the Genesis Narrative as Satan’s attributes e.g., conniving-subtle-deadly are like those of the serpent. If you desire to know what Eve observed in Eden and why she was so enamored by Satan, the Holy Spirit provides us with Satan’s incredibly attractive physiological attributes in Ezekiel 28 and Jesus explains who are the “offspring” or “seed” of Satan in John 8.