Halloween represents many things to many people. For the Celtic traditionalists, it’s a New Year’s celebration of Samhain. For certain Christian denominations, it is a time for solemn remembrance of the dead before All Saints Day. And for retailers in the United States, Halloween is the next best thing to Christmas.

The National Retail Federation estimates that the average U.S. resident will spend $66.54 on Halloween this year. That’s $24.17 on costumes, $20.39 on candy, and $21.98 on decorations, cards, and various other All Hallows accoutrements. All told, retailers should rake in over five billion dollars from the fright fest in 2008.

That’s orders of magnitude less than what will be spent on Christmas in the United States, but it goes a long way towards explaining how costumes, decorations, and trick-or-treating became such indelible elements of Halloween in the United States. There’s money to be made from these traditions, so the profitable elements of Halloween are going to be promoted, encouraged, and monetized.

That said, much of our contemporary Halloween imagery — vampires, werewolves, and Frankenstein monsters — comes from another commercialized culture exporter: the movies. On an evening when we’re all supposed to be wary of evil spirits, Hollywood has done a remarkable job of giving us specific monstrosities to fear and, more importantly, imitate. This is of a piece with the other money-driven Halloween elements, as horror movies are perhaps the most profitable film genre of all time.

That may seem an odd thing to say, when one consults the list of highest-grossing movies of all time and finds not a single horror flick in the top 25. The Sixth Sense is the highest grossing scare film on the list, and it comes in at number 32. If one were to adjust for inflation, The Exorcist jumps way up to a respectable number nine, but only The Sixth Sense and the original 1953 House of Wax join it in the Top 100, meaning horror rarely rakes in the big bucks.

The secret to horror’s success is that fright films are exceedingly cheap to make, so in terms of percentage return on investment, horror films are mind-bogglingly profitable. In fact, the most profitable film ever made, as measured by percentage ROI, is a horror flick.

WHAT IS THE MOST PROFITABLE MOVIE OF ALL TIME, AS MEASURED BY PERCENTAGE RETURN ON INVESTMENT?

Get the answer.

The film in question is none other than the infamously Internet-promoted The Blair Witch Project. Produced on a budget of just $35,000, Blair Witch earned over $248 million at the worldwide box office, for a return on investment of 354,614.29 percent! (This assumes that 50 percent of all proceeds were returned to the studio, which is a pretty standard Hollywood accounting rate.) Put another way, for every dollar spent on making Blair Witch, the movie earned $3,546.14. That’s good enough for a spot in The Guinness Book of World Records as the most profitable movie ever made.

Lest you think Blair Witch is a mere fluke, we refer you to this list of all-time highest percentage ROI movies. Blair Witch is far and away number one, but the original 1968 Night of the Living Dead is fifth, the original Friday the 13th is eleventh, Saw is sixteenth, and Evil Dead is eighteenth. Five of the 20 highest-percentage ROI movies of all time are traditional horror films.

In terms of absolute profit, big-budget blockbusters like Titanic, Return of the King, and Jurassic Park still reign — those three earned the most dollars after breaking even, ever. But those same kinds of movies represent the highest risk, as the top 10 money-losing movies of all time all had budgets of over $80 million, and eight of those 10 had budgets in excess of $100 million.

The top five ROI horror movies we mentioned above had a total combined budget of less than $2.3 million. If you’re a Hollywood producer wondering about the safest place to put your movie money, horror films are perhaps the safest bet you can make.

Moreover, as most Hollywood observers will tell you, anytime a movie makes a significant profit, a sequel to that movie is almost a foregone conclusion. Thus, as horror movies are so easily profitable and affordably produced, is it any wonder that there have been 11 Friday the 13th films (counting Freddy vs. Jason), with a 12th to come in 2009; eight Nightmare on Elm Street films (counting Freddy vs. Jason); nine Halloween films; and now five Saw films (which is remarkable for a franchise that launched in 2004)?

That’s not just some devilishly derivative dreck, it’s a horrifically high-profit hack at Geek Trivia.

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