How does Abigail turn the court against Mary Warren?

Abigail claims that she sees Mary Warren's spirit manifested as a bird, trying to hurt her. Mary Warren sobs that she is merely standing in court, but Abigail continues with the charade. Mary Warren claims that the girls are lying, but after Danforth threatens her and Abigail refuses to stop her charade, Mary submits and accuses Proctor of being the Devil's man.