Look out, it's Friday the 13th this week! But why is the date considered unlucky?

Maybe think twice before spending that hard-earned money on a Mega Millions ticket this Friday.

And maybe rethink those plans to gamble the night away at Hollywood Casino or bet on your favorite sports team.

Why? Because it's Friday the 13th, a day many call the most unlucky day on the calendar.

It's so unlucky, in fact, that the very unfactual story of Jason Voorhees' really bad summer camp experience was made into one of the most successful horror movie franchises ever.

Here are some other reasons why the date sticks out.

The original "Friday the 13th" came out in 1980.
The original "Friday the 13th" came out in 1980.

Why is Friday the 13th considered unlucky?

Jesus.

Yes, the superstition dates back to Christianity.

In 2015, USA Today quoted Michael Bailey, a history professor at Iowa State University who specializes in the origins of superstitions, as saying: "Fear is likely rooted in Christianity. Jesus was crucified on a Friday and ever since the day has been associated with 'general ill omen.'"

In the Middle Ages, weddings were not held on Friday and you never wanted to start a journey on that day of the week, according to Bailey.

The "13" number is in relation to the number of guests who are believed to have attended the Last Supper, the night before Jesus was killed, Stuart Vyse, a psychology professor at Connecticut College, told USA Today. And Judas Iscariot, the disciple who betrayed Jesus, is considered to have been the 13th guest, Vyse said.

When did Friday the 13th begin?

The superstition's origin is unclear. No mentions of Friday the 13th appear before the 19th century.

But somehow, Vyse said, the superstition continues to be passed on from one generation to another. "It would be hard to find someone in the U.S. that doesn't know about Friday the 13th," he told USA Today. "We are all taught about it at a young age."

Is there a medical term for people who fear Friday the 13th?

Yes. It's called "paraskevidekatriaphobia."

How many 'Friday the 13th' movies are there?

There are 12 "Friday the 13th" movies, including a 2009 reboot and the 2003 Freddy Krueger and Jason Voorhees crossover film.

Why the industry is waiting for a 13th "Friday the 13th" movie to be made is a question better suited for a Hollywood insider.

'Friday the 13th' movies in order

Here's a list of the movies in order of their release if you're looking for something to binge this weekend:

  • "Friday the 13th," 1980

  • "Friday the 13th Part 2," 1981

  • "Friday the 13th Part III," 1982

  • "Friday the 13th: The Final Chapter," 1984 (Note: It was not the final chapter.)

  • "Friday the 13th: A New Beginning," 1985

  • "Friday the 13th Part VI: Jason Lives," 1986

  • "Friday the 13th Part VII: The New Blood," 1988

  • "Friday the 13th Part VIII: Jason Takes Manhattan," 1989

  • "Jason Goes to Hell: The Final Friday," 1993

  • "Jason X," 2002 (Note: Jason in space!)

  • "Freddy vs. Jason," 2003 (Note: Is this canon? Who cares?)

  • "Friday the 13th," 2009

A scene from "Friday the 13th, Part VI: Jason Lives."
A scene from "Friday the 13th, Part VI: Jason Lives."

Who is Jason Voorhees?

The original "Friday the 13th" movie has themes of bullying and motherly love. After Jason drowns, his mother, Pamela Voorhees, stalks the camp counselors who let it happen.

Where can I stream 'Friday the 13th' movies?

The movies are available to rent on Amazon Prime, YouTube TV, Apple TV, Vudu or Google Play Movies, and some are available with a Starz subscription or an add-on premium Starz subscription on Hulu or Amazon. You can watch the first "Friday the 13th" movie on Paramount+.

Dispatch reporter Monroe Trombly and USA Today contributed to this report.

This article originally appeared on The Columbus Dispatch: Why is Friday the 13th unlucky? Is it because of Jason Voorhees?