It is an event in which the theme park is transformed into "160 acres of horror", via a series of roaming monsters, terrifying haunted houses[1] and 'scare zones'.

[3] The concept was introduced to the park's operations committee in a meeting in September 1973 by George Condos and Martha Boyd of the marketing department, and Bill Hollingshead and Gary Salisbury of the entertainment office.

Originally a three-night affair, running October 26–28, 1973, Halloween Haunt was an instant hit, and by the next year, the event sold out nightly.

According to postings on her Myspace page, Cassandra was released from her contract by the park's new owners due to their wanting a more family friendly appeal.

Seasonal workers are cast as a variety of monsters, roaming the 160-acre (0.65 km2) park in terrifying scare zones, amidst haze produced by giant fog machines.

[66] Some characters have developed a special appeal, such as the legendary, iconic, and infamous villainess herself Sarah Rebecca Anne "The Green Witch Of Calico" Morgan-Marshall.

[67] The Green Witch character became the most famous of the 1,000 "monsters" at Knott's Scary Farm, and Charlene Parker served in that role for over three decades (1983-2017).

Parker was the subject of two feature articles about her in the Orange County Register, as well as the travel blog of the Los Angeles Times, and other publications, as well as appearing in Knott's commercials.