While in court Mary Warren sews a poppet for her boss, Elizabeth Proctor. She tells Elizabeth, "We must all love each other now, Goody Proctor."
A poppet, or childish doll, is a strange gift to give an adult woman. Children are supposed to act like adults in Puritan society, and the culture does not embrace any type of frivolousness.
The poppet foreshadows future disasters for the Proctors. This seemingly simple gift houses a needle that ends up being the source of Elizabeth's indictment. Abigail goes to dinner with a needle stuck in her belly. She claims that it was Elizabeth's spirit attacking her. The poppet is a source of the innocent Elizabeth's wrongful conviction the same way that many innocent people will fall victim to attacks by things that seem innocent, like the girls who are seemingly innocent in the town, but are actually convicting people in their town.