them) and/or cannot be caught by authorities. Victims commonly experience the "attack" in their bedrooms, homes or other seemingly secure enclosures. They may report being pinned or paralysed, or on the other hand describe a "siege" in which they fought off a persistent intruder or intruders. Many reports can readily be explained psychologically, most notably as the "Old Hag" phenomenon, recorded in folklore and recognised by psychologists as a form of hallucination. In the most problematic cases, an "attack" is witnessed by several people and substantiated by some physical evidence, but the attacker cannot be verified to exist. Counterpart in Prague A similar figure known as Pérák, the Spring Man of Prague was reported to have been seen in Czechoslovakia around 1939–1945. As writers such as Mike Dash have shown, the elusiveness and supernatural leaping abilities attributed to Pérák bear a close resemblance to those exhibited by Spring-heeled Jack, and distinct parallels can be drawn between the two entities. The stories of Pérák provide a useful example of how the traits of Spring-heeled Jack have a broad cultural resonance in urban folklore. Pérák, like Spring-heeled Jack, went on to become a folklore hero, even starring in several animated superhero cartoons, fighting the SS, the earliest of which is Jiří Trnka's 1946 film Pérák a SS or Springman and the SS. In contemporary popular culture The character of Spring-heeled Jack has been revived or referenced in a variety of 20th and 21st century media, including: Spring-Heeled Jack (1989) – a combination prose and graphic novel by Philip Pullman in which Spring-heeled Jack saves a group of plucky orphans from the malevolent Mack the Knife. The Strange Affair of Spring-Heeled Jack (2010) – an alternate history novel by author Mark Hodder, portraying Spring-Heeled Jack as a time traveler. The Springheel Saga (2011) – a three-series audio drama produced by the Wireless Theatre Company. See also Jack the Ripper Jersey Devil Jiangshi Krampus London Monster Mothman Owlman Batman The Shadow References Further reading Bell, Karl. The Legend of Spring-Heeled Jack: Victorian Urban Folklore and Popular Cultures, Boydell & Brewer, Boydell Press, 2012. Berlitz, Charles. Charles Berlitz's World of Strange Phenomena. New York: Fawcett Crest, 1989. . Clark, Jerome. Unexplained!: Strange Sightings, Incredible Occurrences and Puzzling Physical Phenomena. Detroit: Visible Ink, 1993. . Clarke, David. Strange South Yorkshire: Myth, Magic and Memory in the Don Valley. Wilmslow: Sigma Press, 1994. . Cohen, Daniel. The