OK, not that sort of UFO, but Elon Musk, the Federal Aviation Administration, the Air Force Public Affairs Agency, and NASA have together “not ruled out” the thought that something other than an internal malfunction caused the SpaceX Falcon 9 rocket to explode on September 1.

Conspiracy theorists were quick to initiate their own investigation. Footage of what SpaceX has dubbed an “anomaly” seems to show a literal unidentified flying object whiz past the rocket just before it ignites and explodes.

On Friday morning, Musk returned to Twitter after a rare, but understandable week off. “Still working on the Falcon fireball investigation,” he wrote. “Turning out to be the most difficult and complex failure we have ever had in 14 years.” Then, things got interesting: “Important to note that this happened during a routine filling operation. Engines were not on and there was no apparent heat source.” As if that enough fuel for the conspiracy theorists’ fire, he continued: “Particularly trying to understand the quieter bang sound a few seconds before the fireball goes off. May come from rocket or something else.”

Videos of the explosion surfaced on YouTube throughout the week, many of which highlighted the “UFO” that flew by just before the upper segment of the rocket burst into flames. The subsequent explosion, which Musk described as “really a fast fire,” consumed the rocket, destroyed Mark Zuckerberg’s prized AMOS-6 internet-beaming satellite, and damaged the launchpad.

The object is flying extremely fast.
The object is flying extremely fast.

Amid Musk’s Friday morning Twitter updates, one user asked him directly: “There are some videos on YouTube claiming something hit the rocket. Any reality there?” Musk, who often responds to random inquiries on Twitter, chose to answer.

It’s important to understand that no one in their right mind is suggesting the explosion was the work of aliens. The UFO is literally just an unidentified flying object: It could’ve been a fly close to the camera or a really fast bird in the distance. But the other possibility, and the one that the footage suggests, is that it was a drone. If that were the case, things would indeed be “difficult and complex” for Musk.

SpaceX is analyzing footage, attempting to determine what really went down. “We are currently in the early process of reviewing approximately 3000 channels of telemetry and video data covering a time period of just 35-55 milliseconds,” SpaceX wrote. Musk requested that anyone with additional footage email it his way. “Please email any recordings of the event to report@spacex.com.”

Unless Musk and SpaceX can prove that the explosion was not their fault — specifically, that it was an act of sabotage — all further launches will be postponed until at least March, 2017.