Mercury is a 2018 Indian horror thriller film written and directed by Karthik Subbaraj. It stars an ensemble cast including Prabhu Deva, Sananth Reddy, Remya Nambeesan, Indhuja Ravichandran, Deepak Paramesh, Shashank Purushotham, and Anish Padmanabhan, amongst others. Subbaraj presented the film under his own production banner Stone Bench Creations, whilst Jayantilal Gada of Pen India Limited distributed and co-produced the film. It is about the story of five friends who were terrorised by the ghost of a victim, maimed from mercury poisoning.

Karthik Subbaraj insisted on doing a silent film after being inspired by Pushpaka Vimana (1987). He came up with a script of a film based on Kodaikanal mercury poisoning incident and planned up as a dialogue-less film. It was announced in May 2017, with production began the same month and completed within July 2017. Filmed across Chennai, Pondicherry, Kodaikanal, and Kamuthi, the background music for the film is composed by Santhosh Narayanan, with cinematography handled by Tirru and edited by Vivek Harshan, whereas Kunal Rajan was the sound designer.

The film released on 13 April 2018 worldwide except Tamil Nadu, due to the Tamil Film Producers Council strike, and was released in the state on 20 April 2018, becoming their first Tamil release, after the strike. Since the film has no dialogue, the makers found it easier to distribute and release the film under major territories across India. The film opened to mixed reviews, praising the major technical aspects and the cast performances, but the slow pace of the film met with criticism. The film was screened at the Indian Film Festival of Los Angeles on 12 April 2018, ahead of the worldwide release.