Mercury is a 2018 Indian horror thriller film that was written and directed by Karthik Subbaraj. The film, which has no dialogue, stars an ensemble cast that includes Prabhu Deva, Sananth, Remya Nambeesan, Indhuja Ravichandran, Deepak Paramesh, Shashank Purushotham, and Anish Padmanabhan. Subbaraj presented the film under his own production banner Stone Bench Creations, whilst Jayantilal Gada of Pen Studios co-produced the film. The plot is about five friends who are terrorised by the ghost of a victim of mercury poisoning.

Mercury is a fictional story that was inspired by the 2001 Kodaikanal mercury poisoning. Filming was done in secrecy, and was officially announced in June 2017 after filming had ended. Filming was done in locations in Chennai, Pondicherry, and Kumbakonam. The background music was composed by Santhosh Narayanan, cinematography was handled by Tirru, and the film was edited by Vivek Harshan.

Mercury was released on 13 April 2018 worldwide except for Tamil Nadu, where due to a strike by the Tamil Film Producers Council, it was released in the state on 20 April 2018, becoming the first Tamil cinema release after the strike. Since the film has no dialogue, the makers found distributing and release is under major territories across India easy. The film received mixed reviews from critics.