Mersal (English: Zapped) is a 2017 Indian Tamil-language action thriller film directed by Atlee and co-written by Atlee, K. V. Vijayendra Prasad and S. Ramana Girivasan (dialogues). The film stars Vijay portraying three roles alongside Nithya Menen, Samantha Akkineni and Kajal Aggarwal. The background score and soundtrack were composed by A. R. Rahman, while the cinematography was done by G. K. Vishnu and edited by Ruben. The story revolves around two twin brothers in which one is a magician avenging for his father's death and medical crimes. The other one is a reputed doctor who charges meagre amounts from his patients.
The film began production in February 2017 with actors Sathyaraj, S. J. Surya and Vadivelu amongst others in supporting roles. It is also the 100th production of Thenandal Studios Limited. The film was released worldwide on 18 October 2017, coinciding with Diwali.
The film opened to positive reviews with critics praising the performance of Vijay, A.R. Rahman's soundtrack, the cinematography, the social message and Atlee's direction, but criticized the cliché plot and excessive length. The film was a commercial success, grossing ₹254 crore (US$39.5 million) worldwide, becoming the fifth-highest grossing Tamil film and Vijay's highest-grossing film in his career. This movie is also the sixth highest grossing South Indian film of all time. The film completed 100-day theatrical run on 25 January 2018. The film will be released in China by HGC Entertainment.