Waganma is a pretty spoiled kid and he certainly can’t fight. The guy doesn’t know the first thing about what it means to be a true hero and that’s why he won’t be able to defeat Ultraman. You also have to consider the fact that Ultraman is considerably larger than the kid so a single kick is all he would need. I don’t see Waganma ever getting strong enough to make this a proper fight so it will definitely be a very quick win for the legendary hero. Ultraman wins.