There is a good deal of unheralded creativity in
Douglas Adams'
Hitchhiker's Guide to the Galaxy series. One notion, almost a throwaway idea, is the Hooloovoo -- an alien race which is a "hyperintelligent shade of the colour
blue." One is noted to have worked on the design and construction of the primary vehicle employed by the series' protagonists, the starship "Heart of Gold." The Hooloovoo in question was, so the novel tells, refracted into a free-standing prism for the celebration of the launch of the starship (such starship then immediately being stolen by
Zaphod Beeblebrox as an entree to his adventures).
This single offhand mention is the sole reference to the race across the face of Adams' works, and so (Adams being dead) will be all we ever know of it from the source. Which is, I think, a shame, because what a concept it is!! An intelligent
color. How might such a thing even work? Is it the shade of blue itself, however or wherever this might be achieved? How is it preserved, if it comes about in the flash of a
sunset or the mixing of a painter's palate? And how does it set forth its agency in the world? One imagines that one might paint a figurine with this shade, and thereby bring to life the object with the intelligence of the color, but the novel's abbreviated description seems to speak more of a disembodied energy (a thing not unfamiliar to many
science fiction franchises).
But though intelligent energy is a common enough idea in the genre, an intelligent (hyperintelligent, even)
color would likely not fly at all in more serious
science fiction (except, very possibly, in the Universe of
Doctor Who). But Hitchhiker's is a wholly farcical enterprise, a setting where things exist for their humorous value over their scientific defensibility. The scenarios and setups abound for something which could be in your presence on a surface with only the color-savvy able to catch it, and the color-blind unable to perceive it. Though there is no small dose of comic device already in these books, what a waste to not tease out the possibilities of an intellectually radiant shade of blue.