In Arthur Miller's The Crucible, Abigail Williams is a 17-year-old woman who is the niece of Reverend Samuel Parris, who lives in Salem, Massachusetts.
In this play, Abigail becomes the center of attention in the witchcraft scandal that rocks the town. In the trials, Abigail becomes a very believeable witness and she soon discovers that she can manipulate most of her listeners to believe anything she wants them to believe. Unfortunately for many whom the court condemned, Abigail is a liar.
John Proctor knows she is not telling the truth and can discredit her, but to do so he must admit that he had an adulterous sexual relationship with her.
Thus, Abigail Williams' "power" in the courtroom is that she can bend to her will those who are in a position to make life or death decisions, especially Judge Danforth. In the court, she pretends to be freezing; she pretends to see a yellow bird; she claims that Mary is using "a black art to change [her] shape". While Proctor tries to get Danforth to see that Abigail is pretending, Danforth falls for her act:
"A little while ago you were afflicted. Now it seems you afflict others; where did you find this power?"