Not to be confused with redstone flux, a power system used by several tech mods.
Flux is the catch-all term for a chaotic overflow of magic, often produced as a byproduct of risky experiments or negligence when working with aura nodes and essentia. Failure to clean up flux can lead to an infestation of taint.
Flux manifests itself in the world in the form of a fluid, either in a liquid or gaseous state. Contacting it will give mobs the Flux Flu effect. Cleanup can be achieved manually or with the help of a flux scrubber.