Subnautica is a sandbox survival game developed by Unknown Worlds. You're a survivor from a ship that crashed into a planet, gather resources and survive while trying to learn why the ship crashed and how you could escape. Would very much reccommend to anyone with Thalassophobia. The second game; Subnautica Below Zero is going into early access soon which is exciting.
Imagine minding your business and this thing pops up and grabs you with its mandibles. There's way crazier creatures than just this in this game.
Build huge bases and customize them with blueprints and collectibles.
Exploration is a big chunk of this game and it's pretty cool to see the different biomes and their creatures.