Fort_Master_Gustav The canister eventually gets to the bottom of the ocean - pressure is not much a problem thanks to the technology of the Musavians, and they eventually reach what you think to be their little settlement where they lay eggs.
Except it isn't.
Instead, you see a massive city, made of equal parts of metal and bones of deceased species found all across the ocean. In the center, you manage to make out a volcano - an underwater volcano complete with a magma chamber, which could explain how they smelted and forged the metal in large enough quantities to make cities. Great lights span the length of the city, hundreds of thousands of these creatures swam around in their chambers, moving through their rooms, making friends and governing the city.
The creatures that surrounded the canister go in front of a gate - the creatures with the metal spikes and other instruments on their hands let them in, and opened the 'gate' to let them in, and they gestured and flashed their lights happily, with a 'smile' on their faces, as the creatures smile back and then went inside the immense, thousand-year-old volcano city.