“There is a creature alive today who has survived millions of years of evolution without change, without passion, and without logic,” begins a man’s deep and ominous voice. The staccato pulsing music grows louder and faster.

The deathly underwater creature comes closer to the surface. “It lives to kill. A mindless eating machine, it will attack and devour … anything.” A screeching tone plays as the unsuspecting swimmer is attacked.

As this memorable trailer for the 1975 film “Jaws” played worldwide, audiences sat at the edge of their seats, gnawing their fingernails, but wanting to see more. The trailer producers had accomplished their goal of attracting an audience to see the killer shark.

Movie trailers have been crossing the big screen since 1913, persuading and enticing audiences to see the movies they are promoting.

They are advertisements in a highly competitive movie market, said Ramona Curry, associate professor of media and cinema studies. Trailers are expensive to produce because it’s all about the first impression to attract an audience, she added.

Watching a trailer in the movie theater lets the audience consider if they want see the film in that theater, said Melissa Larabee, a teaching assistant in the English department for the UIUC course ‘Intro to Film.’

While movie trailers primarily are an advertisement, they also are viewed as an art form. The Golden Trailer Awards and Key Art Awards are two award ceremonies that celebrate the best film trailers every year.

Curry makes the comparison between movie trailers and music videos. Both give a different artistic slant on the product — movie or song — that the audience might not have originally had.

“That is a way in which it becomes interesting, because then there becomes a dialogue between the production that’s out there that’s promoting the film, and the film itself,” Curry said.

The purpose of trailers can change depending on the type of film.

“If you have a completely original project, you have to introduce people to the concept,” Larabee said. “But if you’ve got an existing property (such as comic books like ‘Watchman’), you also have to appease the fan base in a way.”

Key elements of trailers include a good soundtrack, special effects, casting of popular actors, technically sophisticated and beautiful cinematography, and close-ups that reveal deep emotion.

Following the conventions of the genre is also important. For example, comedy trailers tend to have a few jokes, but do not reveal all of them in the trailer.

While most trailers follow a certain format, producers who ignore the formulas may find that going against the grain despite the risks is what makes them successful.

“The audience now is so savvy to the conventions of trailer making. I really think it is a benefit to movies when they are willing to go out of that box. But it is financially risky for the companies, and so I think that’s why they don’t tend to,” Larabee said.

Though there is a fair share of success stories, there are also many bad trailers that end up dissuading the audience from lining up at the box office. This may be a result of the trailer-making process, which forces trailers to be created early in the film production process, said Kent Ono, professor of media and cinema studies. Scenes may be eliminated, and the actual movie may be quite different from the trailer.

One aspect of a bad trailer is revealing the entire plot of the film. Another is too much stimulus, making the trailer confusing and disorienting.

Yet, trailers might have fast cuts and elaborate special effects to persuade online audiences to go see the film on the big screen. In 2011, movie attendance hit a 16-year low, and ticket sales were approximately a half a billion dollars behind 2010. This put pressure on the movie trailer industry.

“I think it’s much more difficult now for companies to convince people that they want to actually get off the couch, and go pay money to see it on the big screen,” Larabee said. “So, there’s a lot of reliance on showing the special effects.”

While the box office has not done well recently, Curry believes it might return.

“When VHS started coming out, there was a fear that theaters would close, but it didn’t happen. It created more interest in older films, and actually created more interest in cinema. Now we’re having what looks like again a downturn again in interest, but I think it might be a cycle and it might come back,” Curry said.

While trailers may have begun as one of the main marketing strategies for a film, they are only one piece of the marketing process today. According to the Motion Picture Association of America (MPAA), in 2007 its member studios spent 4.2 percent of their marketing budget on theatrical trailers.

“One thing that’s really important now is trailers don’t have to stand alone anymore. Even with ‘Cloverfield,’ there were also all these other marketing campaigns that were going on at the same time, viral things, and so everything is very integrated,” Larabee said.

Movie trailers may be a small part of the movie marketing process, but they are nonetheless essential to the cinema experience — whether the audience views them as art, an advertisement or another genre for them to critique.