Flinx in Flux (1988) is a science fiction novel by American writer Alan Dean Foster.

Flinx finds a woman unconscious on a riverbank deep in the jungles of Alaspin where he has gone to release Pip's offspring.

The woman, Clarity Held, turns out to be a research scientist last working on the inhospitable world of Longtunnel.

He returns Clarity to her research station, only to encounter his old friends, the Ulru-Ujurrians, who help him psychically touch the threat that drove the ancient alien race, the Xunca, from the known universe.

The caverns are home to a wide variety of flora and fauna that redefine the preconceived Humanx notions of evolution and possible lifeforms.

Clarity and Sowelmanu reunite with their fellow scientists, and Flinx discusses the ordeal with Alynasmolia Vandervort.

Vandervort cautions Clarity about becoming too close to Flinx due to his unpredictable and possibly dangerous gene modifications.

Meanwhile, Flinx is asked to take wounded survivors to a nearby planet, Gorisa, which has better medical facilities.

Later, Clarity visits Vandervort only to find that Flinx and Pip have been rendered unconscious by sleeping gas and are in a container.

As they begin to leave, fanatics arrive to "save" Flinx and return him to true normal form.

He extends an invitation to Clarity to accompany him on his journey to understand himself and this new threat, but she declines, needing a break.