Subnautica 2 Guide: How to Find Lucifer Rotsac and Craft Rubber

Quick Answer: Swim about 70 meters East of your Lifepod to find glowing red orbs called Lucifer Rotsac sitting on top of colorful flowers. Grab them by hand, then take them back to a Fabricator where two Rotsacs will yield one piece of Rubber.

You cannot survive long in the alien oceans of Zazura without upgrading your basic gear. Before you can swim faster or dive deeper, you need Rubber. This early-game essential unlocks the Standard Air Tank, the Air Bladder, and your Basic Fins.

Unlike Titanium or Copper, you will not find Rubber just lying around on the seabed. You have to manufacture it yourself using a very specific underwater plant called the Lucifer Rotsac. Here is exactly where to find it and how to process it.

Where to Find Lucifer Rotsac

Thankfully, you do not have to venture far from the safety of your starting area to find this vital resource. The shallow biome surrounding your Lifepod is absolutely full of them.

Grab your compass, dive into the water, and swim about 70 meters directly East. You are looking for a unique, colorful plant known as the Cradle Shootroot. This flora features sea-green leaves tipped with bright orange, and right in the center sits a large, starfish-like bud. That glowing red bulb is the Lucifer Rotsac.

Pro Tip: If you are having trouble spotting them in the dense kelp, wait until nighttime. Both the flower and the bulb glow a bright, radioactive red in the dark, making them incredibly easy to farm when the sun goes down.

Harvesting and Secondary Drops

You do not need any special tools to grab the Rotsac. Just swim up to the glowing red bulb and press your interact key to rip it right off the flower. Each bulb gives you exactly one Lucifer Rotsac for your inventory.

Do not ignore the base plant itself, either. If you take out your Survival Multitool and hack away at the Cradle Shootroot, you will harvest Fibrous Pulp. You can turn this pulp into Fiber for crafting, or cook it into an Oily Salad. Just remember that your character cannot actually digest food until you acquire the Digestion Adaptation from the nearby Angel Root.

How to Manufacture Rubber

Once your pockets are full of glowing red bulbs, head back to a Fabricator.

Navigate to the “Basic Materials” section and open the “Resources” tab. It takes exactly two Lucifer Rotsacs to synthesize a single piece of Rubber.

Keep in mind that while your Lifepod Fabricator has built-in power, any custom seabase will need its own energy grid to process materials. If you are ready to expand your operations, check out our Subnautica 2 Guide: How to Unlock the Habitat Builder and Construct a Base to get your first outpost powered up.

Early Game Inventory Trick

Inventory space is brutal during the first few hours of the game. Lucifer Rotsacs take up valuable slots. I highly recommend processing every single bulb you pick up directly into Rubber immediately.

Later in the game, you will need raw Rotsacs to craft Grease for advanced machinery.

Do not worry about hoarding the raw plants for the future. The Cradle Shootroot regrows its bulbs fairly quickly, so you can always swim right back outside and farm more when the time comes.

For more tips, walkthroughs, and everything else covering the game, check out our full collection of guides.