(paraphrasing)

"Hmm. This system was used to detect undersea vessels in order to guide them in for docking. And it's still active! And.... there's something down there. And it's HUGE..."
- Ghost

This audio is from an inspection point on Titan. The specific point is located near the tank public event on The Rig. If you fast travel to the rig, walk to where the public event flag is, turn around to face the main body of the rig, there's a door pretty much straight ahead of you. Head inside and look at the monitors on the left hand wall.

Added to this audio is the giant object visible behind Sloan when you talk to her on Titan. It's black, and bulbous - almost like a dead insect of some sort. But if you look at the docks it has burst through, it pretty clearly burst out from *below* the waves rather than punched through the docks from above.

Unfortunately, we cannot visit this monstrosity, nor can we delve so deep into the arcology as to see what lies beneath it.

So what lies below the waters of Titan?

Look in the windows when you obtain the cpu core. There's a massive fishy shadow.

Look in the windows when you obtain the cpu core. There's a massive fishy shadow.

Not just that, you can occasionally see it breaching a bit in the waters behind Sloane, and she'll tell you that she can hear it calling out from beneath the waters...

Did we (or the Traveler) bring it during the Golden age? Is this a hive thing?

Did we (or the Traveler) bring it during the Golden age? Is this a hive thing?

Other inspection items mention that the residents of Titan were betting the Traveler would "go there next" so I'd wager the traveler was not yet there.

Hmm... Where else have we encountered giant undersea creatures and the hive at the same time?