The question of how fossil pokemon were colored has long puzzled human scientists, and even those species successfully restored from them face questions about the accuracy of their reconstructions; if Dracozolt and Arctovish can (poorly) function, then how can we be certain about Kabuto's brown shell or Archen's rainbow plumage? Brute Bonnet's DNA has not been successfully extracted, nor do sufficient melanosomes survive – only an illustration in the Scarlet Book, which those scientists who doubt it consider sufficiently mistaken to damn the whole thing as a hoax.
It is well established that Foongus and Amoonguss in Unova's early history were pure white, and that the red and white pokeball look of the modern species is an adaptation in response to the popularity of the Voltorb pokeball. How, then, could a pokemon from the early Paleocene so closely mirror the modern species' colors? Even those who accept the source are divided on whether the artwork is mistaken – perhaps the scientists, fleeing in terror, did not get a good view of Brute Bonnet's head and filled in blanks with species from their own time.
Yet red coloration is also found in other fungal pokemon, and the fact that pokeballs have since become the indispensable companions of trainers everywhere need not mean that a red and white circular pattern evolved only once in the Amoonguss lineage. The spikes on its head are nothing if not evidence that they did not blindly copy their modern counterparts, and their umbrella-like leaf veils, although an increasingly popular reconstruction, do not fossilize; they are inferred by the shape of the underlying helmet. The leaf curtain which may have protected their faces in a dangerous age has no modern parallel; if the Scarlet Book illustration was a hoax, it was surely an imaginative one.