Elite: Dangerous, the spacefaring game from Frontier Developments, has been seeding its world with mysteries since its launch in 2014. With the game’s next update, called The Return, Frontier has promised to finally begin providing answers. I was shown part of that reveal this week at E3, a trailer filled with new structures on planetary surfaces that have yet to be introduced to the game.

Frontier provided little context and refused to answer my questions. They just let the tape roll.

The search for the Thargoids began with the discovery of unusual artifacts floating in space, and then escalated into a series of dramatic encounters with unknown ships — gigantic, flower-shaped vessels capable of completely disabling even the most powerful players. Recently, those ships have even begun to harass players on the surface of planets.

Then, just yesterday, players discovered something even more unusual: a massive, polyp-shaped growth on the surface of an inhabited world.

We’re slightly confused but enthralled by this amazing shot from @TheYamiks. What do you reckon this is, Commanders? pic.twitter.com/SXrI3HXtD2 — Elite Dangerous (@EliteDangerous) June 14, 2017

Alien growths, called barnacles, first appeared on the surface of planets more than a year ago. Recently, Thargoid ships began to visit them. But this structure is much larger. So far, no one seems to have figured out what it is.

Frontier didn’t tell, but the trailer they showed me may have something to do with what happens when they begin to grow.

Attending the private screening were Elite’s co-creator David Braben and senior designer Sandy Sammarco. The clip began with a player flying above a rocky, barren world. As they moved closer to the surface they began maneuvering over what I initially thought might be a crashed Thargoid ship. But the closer the pilot got, the larger the structure appeared.

It was almost as if the surface of the planet itself had opened up like a gigantic mouth, leaving behind a huge crater lined with jagged, tooth-like structures.

I watched, mesmerized, as the ship landed and the pilot disembarked into a tiny, six-wheeled rover. Soon, they were completely underground, driving along inside of a tunnel or a cave. Egg-like sacks popped and splattered beneath the rover’s wheels. Eventually, an unusual, drone-sized vessel called a Scavenger appeared, leading the player through a series of doors toward a large, central room.

And that’s when the video stopped.

Neither Braben nor Sammarco would comment on what it was that I was looking at, only to say that when these structures are added into the game they won’t be giving any hints as to where they are among Elite’s 400 billion star systems. It will be up to the players to find them on their own.

Elite: Dangerous has continued to add features to the game since its launch. The most recent update, called The Commanders, added player avatars and multicrew ships to the game. The Return is expected in the third quarter of 2017. The game is currently available for Windows PC and Xbox One, and will launch for PlayStation 4 on June 27.