The Sci-Fi Channel seems to have reached the outer limits of "reality" TV.

A new show called Scare Tactics, scheduled to premiere on the channel in April, is using hidden cameras to film the reactions of unsuspecting witnesses to horror and science-fiction-style scenarios such as haunted houses and alien abductions.

The trouble is, one of the witnesses contends she suffered real-life trauma from her experience and says she was hospitalized several times as a result of a prank involving an "extraterrestrial murderer."

The resulting lawsuit underscores the growing risks -- and expense -- of television's hottest genre, particularly when these unscripted programs involve everyday citizens who haven't signed up.

In a lawsuit filed in Los Angeles County Superior Court, L.A. resident Kara Blanc claims she suffered emotional and physical trauma when the cable channel and other co-conspirators allegedly abducted her and forced her to witness a staged homicide by an "alien" that she thought was real.

Blanc said she was led to believe that she had won an invitation to an exclusive Hollywood party at a Southern California desert resort.

She said she was traumatized after the car taking her to the party stalled along a remote stretch of desert and she was told by the people accompanying her to run for her life into a nearby canyon to escape harm by an alien attacker.

Named as defendants in the case are the Sci-Fi Channel, two actors who staged the prank and the two creators of the show, Scott Hallock and Kevin Healey, and their production companies. Hallock and Healey were executive producers of NBC's 2001 summer staged-reality hit Spy TV.