The Florida Republican presidential candidate jokingly revealed a federal alien facility during a sit-down with The Des Moines Register editorial board on Wednesday in a moment of levity during a conversation about federal land.
"In the state of Nevada, the United States federal government owns an extensive amount of land, and some of it is legitimately in the possession of the United States," Rubio began in seriousness.
"We have a significant testing range out there," he added, deadpanning: "Obviously we have Area 51 where we keep the alien bodies from the -- I'm just kidding, that's not true."
The Republican sits on the Senate Intelligence Committee and is briefed on classified matters, which he is legally barred from revealing.
Rubio's joke was not the first time aliens have come up on the 2016 trail this week alone.
Democratic front-runner Hillary Clinton pledged to "get to the bottom" of UFOs in an interview in New Hampshire on Monday, in a tongue-in-cheek response to a question from a reporter. Her husband, former President Bill Clinton, and senior adviser John Podesta have also joked about aliens in the past.
Rubio brought up Area 51 unprompted during a discussion about armed men who have taken over federal land in Oregon, they say in a protest of the federal government taking over too much land.
The senator agreed that the government owns too much land, bringing up the early voting state of Nevada as an example repeatedly, but said citizens "can't be lawless."
He said whether or not the men are breaking the law is not up to him, but if they are, they should be prosecuted.
"That's something that belongs to local law enforcement," he said. "I haven't been on the ground there, so I don't know all the details. ... If they are violating federal law, no one is above the law. And if you have violated federal law, and you've committed a crime, you should be arrested and you should be prosecuted for what you've done."
The influential Iowa paper's editorial board regularly sits down with the presidential field and asks them a variety of questions about their positions.