Negative Dye

It does what a photo negative does. Whatever color a piece of gear already is, this flips it to the opposite, so the result depends entirely on what you put it on rather than on the dye itself. Judge it on the armor you actually intend to wear, because the icon tells you nothing about how it will land.

It refuses to mix with anything else, so it cannot be layered the way most of the trader's stock can. That rules it out of any look built from two dyes stacked together.

The shop only carries it on a full moon, one night in eight, which is easy to sleep straight through. In Hardmode the Strange Plant rewards are the steadier source, since you are handing plants in for other things anyway and this turns up in the rotation.