Heard there was a challenge to find a “white animal with rainbow effects” as it is supposedly impossible. So, after scrounging around the internet and collecting an array of images from many forms of media I’d like to present animals that are white (or lighter) and iridescent. I will be working my way from those that are the least iridescent to most iridescent.
Sunbeam Snake - though the one featured in the screenshots is the wild type variety, I would like to direct you to the lighter scales near the belly. Certainly, the iridescent features are more prominent along its back but there are still a pearlescent hue in the lighter scales
Corn Snake - The one featured is a palmetto morph, meaning it’s body is almost completely white but it has flecks of reds and oranges. The belly scales can have an iridescent nature, which is more noticeable in sunlight.
Forest Mother of Pearl Butterfly AKA Pearl Morpho - A stunning white butterfly with the loveliest array of iridescent colors throughout.
Nacre or Mother of Pearl - the innermost lining of mollusks, typically pale in color (is white/off-white when clean).
Evidently a white animal with an iridescent appearance is not impossible and is very much in the realm of possibility (though of course not for wolves). Great Ones are supposed to be a once in a lifetime (more like once in a millennia) harvest, the most legendary and mystical specimens to ever exist. So the colors may not be realistic to the animal in question, but it does exist in the animal kingdom.
My apologies for the very long winded response, have a great day.