Something big is lurking under the moon's deepest crater, and fans of video game Destinycan't stop talking about it.

An anomaly, which astronomers believe to be metal, is hiding under the South Pole-Aitken basin, and could be lodged as deep as far as 300 kilometres (186 miles) under the surface. The study was published in Geophysical Research Letters.

"Imagine taking a pile of metal five times larger than the Big Island of Hawaii and burying it underground. That’s roughly how much unexpected mass we detected," the study's lead author, Peter B. James, said in a statement.

The Twitter account for video game series Destiny, had something to say about the mystery which was lurking below.

Tweet may have been deleted

The news story also got the attention of Destinyfans online.

Tweet may have been deleted

Tweet may have been deleted

Tweet may have been deleted

Tweet may have been deleted

Tweet may have been deleted

To explain, it's largely in relation to the recent announcement of the Destiny 2: Shadowkeep expansion, which is set on the moon.

As you'll spot in the trailer, the moon isn't a great place to be, where "new nightmares have emerged from the shadows of our long-forgotten moon." Really, the research about the moon mass was a great bit of timing.

The mass could've possibly been from an asteroid which crashed into the moon's surface and formed the crater, which was created an estimated 4 billion years ago.

Researchers were measuring the subtle changes of gravity around the moon, when they discovered the mass which sat underneath its surface.

“When we combined that with lunar topography data from the Lunar Reconnaissance Orbiter, we discovered the unexpectedly large amount of mass hundreds of miles underneath the South Pole-Aitken basin," James added. "

"One of the explanations of this extra mass is that the metal from the asteroid that formed this crater is still embedded in the Moon’s mantle."

Whatever the mass might be, it's weighing down the basin's floor by half a mile. The crater, as James notes, is "one of the best natural laboratories for studying catastrophic impact events, an ancient process that shaped all of the rocky planets and moons we see today."

Even though it's huge, the crater can't be seen from Earth -- as it resides on the dark (or more accurately, far) side of the moon.

With the exception of Destinyfans, maybe.