A mysterious “golden egg” has been found 2 miles deep on the ocean floor off Alaska – and scientists still don’t know what it is.

A golden egg, or an alien, at the bottom of the Pacific Ocean?

American scientists have found a mysterious dome structure deep in the sea off Alaska, but no one knows for sure what it is.

Marine researchers using a remote sensing vehicle were surprised last week when they spotted a strange object in a rock about two kilometers deep in the Gulf of Alaska.

One of the videographers on board helping to document the dive referred to what appeared to be a “yellow hat,” the National Oceanic and Atmospheric Administration said in a statement.

It is over 4 inches in diameter and has a small tear near its base.

“As the cameras zoomed in, scientists were overwhelmed by its identification, with first impressions ranging from a dead sponge, to a coral, to an egg,” NOAA said.

“To attract an almost mythical image, this specimen has been called the ‘golden orb’ and the ‘golden egg,'” the agency added.

“Isn’t the deep sea strange?” asked Sam Candio, coordinator of NOAA Ocean Exploration.

As theories circulated on social media, including that it was a strange egg, scientists pulled their August 30 discovery from the sea floor to analyze it in a laboratory setting.

“Although we were able to collect the ‘golden orb’ and bring it aboard, we have not yet been able to identify it beyond its biological origin,” NOAA said.

It remains unclear whether the golden dome is associated with a known species, a new species, or represents an unknown life stage that exists, according to Candio.

“New species have the potential to reveal new sources of medical treatments and vaccines, food, energy, and other human resources and information,” Candio said. “Together, the data and information collected during this expedition will help us close the gaps in our understanding of this part of the planet, so that we can better manage and protect it.”

While researchers hope the discovery will provide new information, they still don’t know what the “golden egg” is.

“While it is somewhat humbling to stumble upon this discovery, it serves as a reminder of how little we know about our planet and how much there is left to learn and appreciate about our oceans,” added Candio.

Jon Copley, professor of oceanography and science communication at the University of Southampton, echoed Candio’s words.

“We often find things in the deep sea that we haven’t seen before or don’t understand immediately, because the deep sea is huge and we’ve only been exploring what lived there a few centuries ago, unlike life on Earth.”, Copley told the Washington Post.

The dive was part of a trip to the Gulf of Alaska to explore deep-water habitats.

NOAA said the expedition will continue through September 16, with livestreamed, remotely piloted vehicle dives occurring daily.