Lucifer Rotsac is a very important plant in Subnautica 2, since it's used to make rubber. That's pretty handy when you're trying to survive on a hostile alien water planet and desperately create sealed environments so you don't drown. But it's not immediately obvious where you're meant to find it.
Thankfully it's actually really easy to collect wholesale, so you won't need to do tons of back and forth, unlike silver, which will be the main hurdle in your initial hours under the ocean.
