Can you explain the story of Karnik meeting a saint in Nashik who demanded a rupee from him?

Certainly. This incident is recounted in Chapter 33 of the Shri Sai Satcharitra. A devotee named Karnik traveled to Nashik and went for Darshan at the temple of Kala Rama. There, he had an unexpected encounter with the saint Narsing Maharaj. In the midst of a crowd of devotees, the Maharaj suddenly got up, grabbed Karnik by the wrist, and demanded, "Give my Rupee." Karnik, though amazed, joyfully gave the rupee, feeling as if it were Sai Baba himself accepting the offering. The text even clarifies that it felt less like a simple acceptance and more like the money was forcefully taken, highlighting the surprising and powerful nature of the divine interaction.