RJD chief Lalu Prasad, lodged in Ranchi's Birsa Munda jail since he was convicted in the multi-crore fodder scam, had a surprise visitor on Sunday. President Pranab Mukherjee's son and Congress MP Abhijeet Mukherjee spent over half an hour with the Rashtriya Janata Dal (RJD) chief in jail. The visit was described as "courtesy call."