Subnautica: Below Zero

For this, you will need to have at least dealt with the "Alien Distress Call" marker in the Twisty Bridges area, or have happened across this location and triggered the relevant story event here.

Once you have done this, you will need 3 Blueprints to construct the item in question. They are obtained in the Arctic Spires (head over the bridge you can repair using the hydraulic fluid, then head to the North/Northwest area, the cache containing the object you need to scan is in a little crack in the ice, illuminated with green light), the Deep Lilypad Caves (under the Pilot last known location beacon, head deep under and explore the cave system, looking out for glowing Alien light fixtures, around 480m deep) and the Crystal Caverns, down a tunnel ringed entirely in purple crystals, the entrance at around 780m or so. Once you have all the parts, assemble the required materials and head down into the Deep Crystal Caverns, where the gems are red and not purple (entrance in the Northeast corner of the crystal caverns) to the structure there and assemble the blueprints using the consoles on your left.

If you want to minimize the amount of backtracking you have to do, before heading down to the Crystal Caverns (use a Prawn Suit for this, the Seatruck attracts too much attention from the residents), bring with you components enough for a small seabase powered with a Bioreactor, a Modification Station and the following:

1 Ion Cube
1 Synthetic Fibres (1 Fibre Mesh + 1 Spiral Plant Clipping)
1 Plasteel Ingot (5 Titanium + 2 Lithium)
1 Polyaniline (1 Gold + 1 Hydrochloric Acid (itself 3 Young Cotton Anemone and 1 Salt))
2 Ribbon Plants
2 Root Pustules
2 Gel Sacks
3 Diamonds

If you have forgotten anything, all but the Root Pustules and Cotton Anemones are found in the Crystal Caverns or the Deep Purple Vents biomes. You will also need to gather 4 Kyanite and 2 Nickel Ore while here, 3 Kyanite for one of the parts, the rest for Prawn Depth Mk2.

This achievement is for completing the new body that your ‘visitor’ needs in order to leave you alone. Once you have the blueprints and materials for all three body components, head back to Marguerit’s base and find the tunnel that goes deeper and leads to a cave with large purple crystal formations.

Note: The next areas are patrolled by Shadow Leviathans and are highly dangerous. I’d suggest leaving the Seatruck and using the Prawn suit from here on as it’s easier to manoeuvre and hide among the crystals.

Your aim is to keep going deeper until you find an area with massive red crystal formations. The base where you can build the body is at the bottom of this area and you’ll need to have the Prawn’s MK 2 depth upgrade to get to it. Park your Prawn somewhere out of the Leviathan’s sight while you’re in the base as they’ll probably keep attacking it and you don’t want them destroying your ride home.