The "Insidious" movie franchise is a popular horror series that began in 2010 with the release of the first film simply titled "Insidious." The franchise consists of four films as of my knowledge cutoff in September 2021:

  1. "Insidious" (2010): Directed by James Wan and written by Leigh Whannell, this supernatural horror film follows the story of a family whose son falls into a coma and becomes a vessel for malevolent spirits. The family must uncover the truth about the haunting and find a way to save their son's soul.

  2. "Insidious: Chapter 2" (2013): Continuing the story from the first film, this sequel delves deeper into the supernatural realm and the haunting of the Lambert family. It explores the dark secrets of the past and the connection between the present and the spirit world.

  3. "Insidious: Chapter 3" (2015): Serving as a prequel to the events of the first film, this installment follows a teenage girl who seeks the help of parapsychologist Elise Rainier as she faces a malicious entity haunting her family. It provides backstory and further explores the mythology of the franchise.

  4. "Insidious: The Last Key" (2018): The fourth film in the series focuses on parapsychologist Elise Rainier, who returns to her childhood home to confront a malevolent spirit that has plagued her throughout her life. It delves into Elise's backstory and her personal journey in dealing with the supernatural.

The "Insidious" movies are known for their atmospheric horror, jump scares, and exploration of the spirit world. They have been successful at the box office and have garnered a significant following among horror movie enthusiasts.