From The Grindhouse Cinema Database
Emergo was promotional gimmick used for William Castle's House on Haunted Hill original theatrical release.  In some theaters that showed the film, exhibitors rigged an elaborate pulley system near the theater screen which allowed a plastic skeleton to be flown over the audience during a corresponding scene late in the film. Several modern repertory cinemas including the Film Forum and Loew's Jersey Theatre have hosted revival screenings of the film during which the "Emergo" gimmick has been recreated.
- Law, John W. (2000). Scare tactic: the life & films of William Castle. San Jose [Calif.]: Writers Club Press. pp. 66–67. ISBN 0595095445. OCLC 60884288.
- Hal Erickson. "House on Haunted Hill (1958)". Allmovie. Retrieved 7 July 2012.
- Village Voice, 25 August 2010
- Cinema Sentries, 30 October 2011