More than one million Facebook users say they're going to raid Area 51 in Nevada on Sept. 20 in a quest to see aliens.
The clearly tongue-in-cheek Facebook event page is titled "Storm Area 51. They Can't Stop All of Us" and states "We can run faster than other bullets."
It's inviting users from around the world to join a "Naruto run" into the area. That's a Japanese Manga-inspired running style featuring arms outstretched backwards and heads forward.
"We will all meet up at the Area 51 Alien Center tourist attraction and coordinate our entry," according to the event organizer.
But some social media users expressed concerns.
"Folks, bad news," Facebook user Jen Petrilli, posted on the event's discussion page. "This event is planned for September 20th. While I love this planning time, this gives them a lot of time to move the aliens out of Area 51. If we want to get our extraterrestrial pals into safe and loving arms, this needs to ASAP. Love, A friend to the aliens."
The mysterious Area 51 has been the subject of conspiracy theories for decades.
Many people believe the U.S. government stores its secrets about UFOs and aliens at the military site.
The invitation comes a few weeks after a group of U.S. Senators were briefed about reported encounters between the U.S. Navy and an unidentified aircraft or unidentified flying object.