Silverstreak

Silverstreak, rather than being it's own animal, is rather a type of mutation seen in wildlife around Silvergrove. Silverstreak can be any variety of wildlife: squirrels, raccoons, deer, boar, bears, fish, even plants and insects can attain this unique coloration. As the name implies, Silverstreak animals will have silver streaks across their coat, skin, or scales; it even goes into their muscle and organs. This usually doesn't have any effect beyond making an object look particularly dazzling; the meat has no altered taste, the animal seems unaffected (beyond the lower stealth of being reflective in places) and the pelt, hide, or wood is not any stronger than normal.
No two animals have the same patterns, and there are even complex forms that will take shape, such as curves, spirals, and even patterns of shapes, although each is more highly irregular and exceptionally rare than the last.
Silverstreak animals tend to form more streaks over time, although this only seems to happen to wildlife in the vicinity of Silvergrove, much to the chagrin of exploitive businessmen, overly peacocking nobles, and dedicated conservationists trying to ranch the animals or farm the plants. Even more oddly, it seems to not be genetic; even ensuring both parents were Silverstreak did not produce Silverstreak offspring in captivity or the wild.