Priyanka Bari's needle was a magical needle that was given to Macy Vaughn by Elder Priyanka Bari. It was used to enhance Macy's power of The Evil Sight. It was eventually broken by Macy, when she began to have demonic blackouts as a symptom of all of the usage of her Evil Sight.
In Switches & Stones, Macy Vaughn and Charity Callahan acquired the help of Elder Priyanka Bari to figure more out about Macy's demon side. Elder Bari figured out that Macy had a power called The Evil Sight which can allow one to see evil acts from the past or present, she told her that the Vortex Viribus had unlocked it. She gave Macy the needle in order to help Macy use her newfound power to help with the fight against evil. This helped Macy find out that Charity was the one who killed her and her sisters' mother, Marisol Vera. As soon as Elder Bari found out, Charity appeared and magically snapped her neck and then erased Macy's memory.
After having her memory erased by Charity, Macy's status as a Charmed One began to allow her memories to return in fragments in Memento Mori. After more memory fragments came back to Macy and she found Elder Bari’s needle hidden under the couch in the attic. She performed the booster on herself, causing the complete memory from that night to come back to her — including learning that Charity killed Marisol and Elder Bari. During her vision of that night, she recounted as Charity performed a spell after killing Elder Bari but she was able to distract her, hiding the needle under the couch and burning herself with the candles to help her remember.
Later, after Macy and her sisters successfully stripped Charity of her powers, Macy explained to Maggie and Mel what she saw happen to their mom. When they asked to see, Macy was able to boost her Evil Sight with the needle and share her vision with her sisters. While their mom was reciting the Power Unbinding Spell, her use of the spell prompted Charity to arrive. Charity revealed that she had been spying on Marisol, due to her ties to the Sarcana. Marisol told Charity about Macy’s death and revival due to necromancy, which horrified her. When Marisol continued, revealing her three daughters are the Charmed Ones, Charity was further alarmed, worrying about the dangers that would come from the Charmed Ones being "tainted" by demons. When Marisol wouldn’t stop the unbinding spell, the two fought and Charity sent Marisol out the window, where, in her dying breaths, she finished the spell. Shocked by what she’d done and under the impression that she had stopped Marisol in time, Charity fled the scene just as Maggie and Mel arrived back home. Having finally learned the truth about her death, the sisters consoled one another, taking comfort in their mother’s bravery.
In Source Material, Macy used the needle to share a vision of Fiona Callahan's massacre of the Sarcana with her sisters. She later used the needle again to learn that Hunter Caine was the one that murdered Julia Wagner.
Macy's demonic powers began to take control of her in Ambush, much to the concern of Harry and her sisters. While Macy was convinced she had her demon side under control, Mel and Maggie worried that Macy’s continued use of her Evil Sight was to blame after her demonic side surfaced without her even noticing — while ranting about the lack of almond milk in the house.
Macy used the needle to perform a painful ritual to render Fiona mortalm, ignoring Harry's concerns. However, the dark ritual had some demonic side effects on Macy and, despite Harry’s pleas, she awakened her Evil Sight to view the aftermath, and regain control. She saw Alastor Caine entering the crypt that the weakened Fiona was hiding in, bragging about finding the Origin Dagger. However, the now mortal witch revealed that she was the steward from the prophecies, who was meant to activate The Source of All Evil on his behalf, thus confirming for Macy her and her sisters' theory that the Source and the Sacred Flame were one and the same.
When Macy removed Elder Bari’s needle from her forehead, her demonic powers continued to fight for control over her body and she lost consciousness.
Later, Macy wanted to use her Evil Sight to learn how Hunter got so powerful and to find out what he was after. However, Mel and Maggie cautioned her against it, citing their very reasonable concerns about her continued use of her demon powers. After an angry, increasingly tense exchange, Macy’s demonic side surfaced and she attacked Mel.Seeing Mel and Maggie genuinely terrified of her was enough to snap Macy out of the demonic fog, and she then broke Elder Bari’s needle, putting her ease of access to her Evil Sight to an end.