The "magic potion" mutation is the dalmatian gene expressed in A. vulgare. Vulgare naturally have yellow dots present in the wild expression, and the dalmatian gene only affects the distribution of dark pigment, so as a result magic potions are an all white animal sprinkled with yellow and black dots. The "American" line of magic potion gets slightly larger than the Japanese variety, and has larger, more frequent dots. Unfortunately, the American line is a bit male heavy and slower to breed as a result. Our culture of American magic potion also tend to throw out some orange spotted dalmatians rather than black ones.