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Subnautica 2 Map
Safe · Shallow reefs

Flash Slug

Bioluminescent grazer used as a portable light source.

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Flash Slug render

About Flash Slug

SafeShallow reefs

Flash Slugs are small bioluminescent grazers that congregate in shallow reefs, especially around coral and Quartz nodes. They are completely passive and serve mostly as opportunistic light: holding one for a few seconds illuminates a much larger area than a Flashlight battery would, with no power cost. They cannot be tamed, but they will follow shoals, which makes them a soft indicator that a route through a tunnel is safe — flash slugs leave when bigger predators arrive. Catch one for a scan and any nearby fish should still be safe to harvest.

How to handle an encounter

  • · Approach freely for scans and harvest.
  • · Use the species as a soft biome cue — sudden absence usually signals trouble.
  • · Cooked or salted variants stack well for long dives.

Drops / harvestable items

1
Flash SlugOrganics

Used in recipes

1
Isotonic WaterOther

Spawn biomes

1
Overgrown Ruins
All creaturesLeviathan reportsBiome guide

Sources

  • External research snapshotThird-party research
    retrieved 2026-05-16