Around 150 drones lit up the sky forming the "Brahmastra" logo at Kumbh on Maha Shivratri on Monday as actors Alia Bhatt, Ranbir Kapoor and director Ayan Mukerji came together for a one-of-a-kind film marketing initiative. "Brahmastra", releasing this Christmas, is a fantasy adventure trilogy. The film by Fox Star Studios also stars Amitabh Bachchan and Nagarjuna.