@CerusSerenade: We've been over this, Augus hasn't busted a planet either, so you can't just assume he has to be planet level to win.
@Low: We all know how beat punch works, no need to explain that. But if you think about it, that's better than an attack that hits durability isn't it? You're just thinking too much about it. The reason Zebra doesn't need to 'evolve' like you say is because of all four, he's always had the highest DC among them. The point of making him powerful without giving him hax is to keep him from being TOO OP. Plus, just because he only uses sound attacks, that doesn't make him a one trick pony.
Even if Beat Punch did get reflected, which I kinda doubt because the vibrations would most likely destroy his feelers and his head, Zebra could beat him other ways. He only reflects physical attacks. And comparing him to the Blue Oni who just punched an Eight King is noooot really fair