Until the final battle of EarthBound, you'll never see Giygas. You'll hear about him quite a bit, but you won't see him until the fateful final battle of EarthBound. And before asking, yes, the wait is worth it. For Ness's party to go to such great lengths to face Giygas, Giygas himself would have had to be one of the best villains in the history of gaming for the effort to be worthwhile. Thankfully, a player who hasn't had Giygas spoiled in advance cannot possibly be prepared for what awaits him. "YOU CANNOT GRASP THE TRUE FORM OF GIYGAS' ATTACK!" - EarthBound (giygas.ytmnd.com)