This is the scripture reference:
God said to satan....
"And I will put enmity between you and the woman, and between your offspring and hers; he (Jesus) will crush your head, and you will strike his heel." Gen. 3:15
We as Christians, know that this verse points directly to the promise made of Christ, as the Deliverer of fallen man from 'the power' of Satan, through His death, and resurrection....(a fatal blow against satan).
So even today we have a 'generation of vipers' on the one hand, and the people who are God's people in Christ on the other.
Oh my! Good catch. I do believe the Catholics teach that it is the woman who crushes the serpents head. Another obvious error but that teaching would be reflected in the statue of Mary with her foot on the serpent.