The Survival Multitool is Subnautica 2’s equivalent of the survival knife, broadened into a multi-function harvesting tool. It gathers the tougher materials that cannot be collected by hand, and its outputs feed into nearly every crafting recipe’s resource inputs.
It is day-one craftable at the Fabricator. Note one important limitation: it will not remove a lodged Tongue Thief parasite — that requires the Sonic Resonator. Striking wildlife with it can also cause permanent aggro, so it is a harvesting tool, not a weapon (Subnautica 2 has no weapons).