Runaway Mould is easy to miss entirely and awkward to look up once you have, which is a common combination in No Man's Sky.

Short answer

In practical terms: know what it does, know where it appears, and the rest is context.

  • Ignore the myth attached to it; it has never held up.
  • Note where it first appears, so you can go back if you need to.
  • Prefer the in-game option over an external tool when both exist.

No Man's Sky has been rewritten by updates so many times that old guides describe a different game. It is the kind of thing veterans forget they ever had to learn. The name is descriptive if you already know what it does, and opaque if you do not.

How it has changed over time

Half the pages on this topic were written for a build that no longer exists, which is why they stop matching what you see. Most guides mention it in passing and none of them stop to define it. The in-game description is technically accurate and practically useless. Screenshots age faster than text, which is why this describes rather than shows.

It is more consequential in the late game than the early one, which is why first impressions mislead. There is a persistent myth attached to it that has never been true in any version. If your result differs from what is described here, note what is different first rather than starting over.

How it connects to the rest of No Man's Sky

Early impressions of it are usually wrong in the same specific way. Its role has changed across updates, so older discussion describes something slightly different. Nothing here assumes a particular playstyle beyond wanting the thing to work.

  • Do not confuse it with the similarly named thing — that mix-up drives most bad advice.
  • Expect its role to have shifted at least once across updates.
  • Expect one number in every guide to be out of date; the method is what matters.
  • Do not build a plan around it before you have seen it work.
  • Check which version of No Man's Sky any discussion of it is describing.
  • Check the version you are actually running before assuming anything is broken.

What it changes in practice

It shows up in more places than its introduction suggests, once you know to look. It rewards understanding rather than grinding, which is unusual for No Man's Sky. What follows assumes you are on a current install and have not modified it. Two similarly named things exist, and mixing them up explains a lot of contradictory advice.

Whether it is worth going out of your way for depends entirely on how you are playing. The short version is near the top on purpose; the reasoning is there if you want to know why. Community shorthand around it has drifted far enough from the original meaning to cause arguments.

What it is

If you only remember one thing about it, remember where it appears. There is usually a fast way and a reliable way, and it is worth knowing which one you are choosing. It appears in supplementary material in more detail than it does in the game itself.

Knowing this does not make you better at No Man's Sky, but it does make the rest of it legible. It helps to understand why a step exists, because then you can adapt it when your situation is slightly different. Its practical value is narrow and real, rather than broad and theoretical.

Why people keep asking about it

The game introduces it quickly and assumes you picked it up, which is where the confusion starts. There is no hidden trick here that the game is keeping from you. It became noticeably more relevant after a change the patch notes barely mentioned.

Where people go wrong

  • Changing five things at once and then not knowing which one helped.
  • Treating a rare edge case as the normal behaviour and planning around it.
  • Trusting a video thumbnail that promises a result the video never actually shows.

No Man's Sky FAQ

Has it changed recently?

Its role has shifted across updates more than once. Anything you read without a version attached may describe an older form of it.

Is it important?

More than its screen time implies, less than the discussion around it implies. Somewhere in the middle.

Can I miss it?

Where it is missable, that is noted above. Most players meet it without going looking for it.

How long does this take?

Minutes if it goes cleanly, an evening if you hit the edge case in the caveats list. Neither is unusual.

Work through it in the order above and runaway mould stops being a question you have to look up again.