A Dalek, a Cyberman and a Silent invade the Melbourne Cricket Ground on Feb. 2, 2012 in Melbourne, Australia Getty Images

If you were skiing in a certain part of Sweden Thursday and looked up, you may have sighted an "oidentifierat flygande objekt," or unidentified flying object. But don't be alarmed — it (probably) wasn't an alien spacecraft.

A lenticular cloud formed over Duved in the Åre municipality Thursday, inspiring social media jokes, scientific discussion and a lighthearted debate about whether extraterrestrials were trying to join skiiers on the slopes.

"I thought it was pretty cool," visitor Elvira Kuper told a local broadcaster, according to the Local.

"That's a cloud? I think the apocalypse is near," user bonesflint commented on an Instagram photo of the phenomenon.

In truth it was indeed a lens cloud, formally called altocumulus standing lenticularis, which form when stable, moist air travels over a mountain range and creates waves. If it's cold enough at a certain part of the wave, the water in the air condenses to make the cloud, according to

The weather oddity wasn't new. Lens clouds have cropped up — and made headlines — recently in places like Cape Town, South Africa, and Sicily, Italy, as various residents have spotted them in the skies and scientists have tried to assuage people's alien concerns.

"Have you seen the alien space craft hovering over the mother city today? Fear not! You are NOT about to be abducted," CNN weather anchor Derek Van Dam wrote in a 2015 Facebook post after a cloud sighting.

Though it didn't occur in Sweden Thursday, hole-punch clouds are also a common explanation for UFO sightings. Hole-punch clouds, or fallstreak holes, occur when planes pass through freezing layers of clouds and have caused similar panic, according to National Geographic.

However, some people aren't alarmed — they were curious and insistent that even though the lens cloud wasn't a UFO, it could still be a coverup for aliens. As Scott C. Waring, who runs the UFO Sightings Daily website, has argued, "It's a well-known fact that not only do UFOs hide in clouds, but they actually create the cloud around them."