Phantasmagoria is a point-and-click adventure horror video game designed by Roberta Williams for MS-DOS and Microsoft Windows and released by Sierra On-Line on August 24, 1995. It tells the story of Adrienne Delaney (Victoria Morsell), a writer who moves into a remote mansion and finds herself terrorized by supernatural forces. It was made at the peak of popularity for interactive movie games and features live-action actors and footage, both during cinematic scenes and within the three-dimensionally rendered environments of the game itself. It was noted for its violence and sexual content.

Williams had long planned to design a horror game, but she waited eight years for software technology to improve before doing so. More than 200 people were involved in making Phantasmagoria, which was based on Williams's 550-page script, about four times the length of an average Hollywood screenplay. It took more than two years to develop and four months to film. The game was originally budgeted for $800,000, but it ultimately cost $4.5 million to develop and was filmed in a $1.5 million studio that Sierra built specifically for the game.

The game was directed by Peter Maris and features a cast of twenty-five actors, all performing in front of a blue screen. Most games at the time featured 80 to 100 backgrounds, while Phantasmagoria includes more than 1,000. A professional Hollywood special effects house worked on the game, and the musical score includes a neo-Gregorian chant performed by a 135-voice choir. Sierra stressed that it was intended for adult audiences, and the company willingly submitted it to a ratings system and included a password-protected censoring option within the game to tone down the graphic content.

Phantasmagoria was released on seven discs after multiple delays, but it was a financial success, grossing $12 million in its opening weekend and becoming one of the bestselling games of 1995. Sierra strongly promoted the game. It received mixed reviews, earning praise for its graphics and suspenseful tone while being criticized for its slow pacing and easy puzzles. The game also drew controversy, particularly due to a rape scene. CompUSA and other retailers declined to carry it, religious organizations and politicians condemned it, and it was refused classification altogether in Australia. The sequel Phantasmagoria: A Puzzle of Flesh was released in 1996, although Williams was not involved.