Having already overtaken Facebook, the crazy "Storm Area 51" event has prompted warnings from the U.S. military and caused one UFO expert to say it's "getting somewhat out of hand."

Oddsmakers are taking the madness a step further.

BookMaker.eu has placed odds on a few different scenarios, including the number of people who sign up, the number of arrests and whether aliens will actually be discovered.

AREA 51 EXPERT ON SOCIAL MEDIA CAMPAIGN TO 'STORM' TOP-SECRET SITE: MILITARY WON'T LET ANYONE GET CLOSE

As of July 17, the over/under on sign-ups for Storm Area 51 was at 2.3 million ahead of the Sept. 20 event, with the over at -160 and under at +130. That means a better who bet $100 would win back their original bet plus $130 if less than 2.3 million people attend.

According to the Facebook page, there are currently 2.1 million people who have said they will attend the event, with another 1.5 million people indicating they're interested.

With regard to the number of arrests, based on what USA Today reports at the time of the event, the over/under is set at 9.5, with the under attracting most of the money, offering -350 odds. This is surprisingly low for an event for which over 1 million people may "attend."

As of Sept. 17, Panama City-based BetOnline.ag set the over/under for arrests at 8.5 people. Both bets offer -120 odds, meaning a better would have to bet $6 to return $5.

The betting site also offered bets of whether “Will anyone illegally access Rachel military area?” with Yes at +500 odds and No at -1000 odds. There was also a bet on whether President Donald Trump would tweet about the event, offering slightly different odds.

U.S. Air Force spokeswoman Laura McAndrews recently issued a statement saying the Air Force "would discourage anyone from trying to come into the area where we train American armed forces," adding that it [the U.S. Air Force] "always stands ready to protect America and its assets."

4 THINGS TO KNOW ABOUT AREA 51

The whole purpose of this hairbrained event is to "let's see them aliens," a question that Bookmaker.eu doesn't believe will be answered.

The odds on "No" are an overwhelming -40,000, meaning a person would have to bet $40 just to win $1. But if for some reason the people manage to get through and E.T. is found running around, bettors will be rewarded handsomely, with the odds on Yes at +4000.

Happy betting.

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This story has been updated from July 17 to include additional betting information.