Marco Rossi from the Metal Slug series!
Several things in the Metal Slug series can transform the player. Yetis in MS3 turn you into a snowman, eating too much food makes you fat, and there's a boss in MS 3 that makes you explode in a shower of gold. Why does this matter? A couple enemies change you completely. Zombies can turn you into a shambling corpse, Mummies turn you into bandage wrapped creeps, and there's a mad scientist in MS4 who turns you into a chimp. Where's the magic come in? To return to normal after being mummified, you must find and chug a mystic potion.
As for age, i'm not entirely sure. There don't seem to be many concrete dates in the series.
