In Act Two of "The Crucible," how is Abigail Williams becoming the villain?
We got the impression in Act One that John Proctor and Abigail had an affair. It becomes clear, at least to Elizabeth, that although Abigail and the other girls initially made accusations of others in order to avoid getting into trouble, it seems that Abigail might see this as an opportunity to accuse Elizabeth and then have John to herself. In Act Two, Elizabeth tries to convince John to talk to Abigail and make things right before it is too late. She says, "You have a faulty understanding of young girls. There is a promise made in any bed-" Then she says, "Spoken or silent, a promise is surely made. And she may dote on it now---I am sure she does---and thinks to kill me, then to take my place."
Shortly after this conversation, Reverend Hale shows up and tells them that Elizabeth's name has been mentioned in court.
Also, in court, Abigail clutches her stomach in pain and blames Elizabeth for it, knowing that Mary had planted the doll in Elizabeth's home with a needle in it, indicating witchcraft. When John Proctor tries to convince Mary to tell the court about the planted doll, Mary tells him that Abigail will charge him with lechery (adultery).
In Act One, we hear a great deal from Abigail about how awful Elizabeth Proctor is, how much Abigail herself still cares for John Proctor, and how she feels about her dismissal from the Proctors' employ. However, we ourselves have no opinion of Elizabeth yet because we haven't met her. Therefore, it is possible that everything Abigail says about Elizabeth is true and that Elizabeth is actually the villain.
Later, in Act Two, though, when Elizabeth actually appears in the text, we can see how much she wants to please her husband, how kind she seems to be, and how innocent of wrongdoing she is. When we learn that Abigail has accused Elizabeth of witchcraft, we know enough about them both now to understand that Abigail is vindictive, cruel, and remorseless. The image of the innocent Elizabeth being chained up and carted away to a nasty jail is horrific because we understand how guiltless she is and how deceptively Abigail has behaved in order to bring about these events. Once we are able to identify Elizabeth as a victim, Abigail becomes more and more clearly the villain.