In the second act of The Crucible, what does Mary Warren give to Elizabeth?
Mary Warren brings Elizabeth Proctor a doll. Referred to as a "poppet" in the play, the doll turns out to be part of Abigail's plan to accuse Elizabeth and get her "out of the way" so that she can re-kindle her affair with John Proctor. Abigail's plan works insofar as it succeeds in getting Elizabeth arrested.
Proctor is therefore not being entirely metaphorical when he says:
“the little crazy children are jangling the keys of the kingdom, and common vengeance writes the law!”
The second act of the play explores the extent to which Abigail and other accusers are given credence while those accused are denied credulity and denied justice.
Mary Warren brings the doll into the Proctor home after spending a day at court, sitting near Abigail. Later that same night authorities arrive at the Proctore home when Reverend Hale is also present. A story emerges that Abigail has become sick at the dinner table with stabbing pains in her belly.
Abigail has accused Elizabeth Proctor of witchcraft on/against her. The authorities then come looking for a doll at the Proctor home and find the one that Mary Warren has brought into the house.
The doll, it turns out, has needles stuck into its belly beneath the dress. This is taken as evidence against Elizabeth and she is taken to jail.
The poppet represents the lengths to which Abigail is willing to go to seek vengeance. It is now clear that the doll was planted in the house by Mary Warren. Abigail has stuck her own belly with a long needle. (eNotes)
When Mary Warren gets home from a long day in court, she gives a handmade doll to Elizabeth Proctor, her employer. She tells Elizabeth, "We must all love each other now, Goody Proctor," and she seems upset by all she has witnessed—Miller describes her voice as "trembling" and "decayed." Mary seems convinced, truly, that Sarah Good was using witchcraft as she sat in court, denying the charges against her, convinced that Good had, in fact, cursed her once before. Mary seems to offer the doll as a kindness to Elizabeth.
Later, after Reverend Hale has come and Mr. Cheever has arrived to arrest Elizabeth, Cheever finds a needle stuck into the doll's stomach, and he calls it a "calamity" because Abigail Williams was found with a long needle stuck into her stomach as well, and she said that Elizabeth's specter did it. Elizabeth fetches Mary to explain the doll, and Mary says that she actually put the needle there herself; she even tells them to ask Abigail, because Abigail saw her do it, sitting next to Mary in court. This would seem to confirm, for most reasonable people, that Abigail is trying to make Elizabeth appear guilty of witchcraft; unfortunately, the characters in this play are not exactly reasonable people.