Throughout his Dragon Ball career, Goku has taken on a number of increasingly deadly villains, so it is no surprise that his earlier enemies aren’t nearly as threatening as some of his later opponents. But in one instance, that power disparity is absolutely ridiculous as Goku’s first archenemy has a weakness so simple even fans could beat him.

One of the first real threats Goku ever faced was King Piccolo who made his debut in Dragon Ball chapter 135 by Akira Toriyama. King Piccolo was a Namekian who, long before his first appearance, threw the world into utter chaos before being locked away in an eternal prison to stop his reign of terror. When he returned, King Piccolo sought to pick up right where he left off, though he didn’t account for a new fighter, Goku–who at this point was just a child but still rose to the occasion and challenged him. In the end, Goku killed the monstrous villain by shooting himself through the villain’s chest, bringing King Piccolo’s evil reign to a brutally violent end.

In Super Dragon Ball Heroes: Dark Demon Realm Mission! chapter 8 by Yoshitaka Nagayama, Xeno Gohan and Xeno Trunks–who are members of an interdimensional police force known as the Time Patrol–are on a mission to hunt down wish-granting artifacts of power known as the Dark Dragon Balls, which have been scattered across time and space. Xeno Gohan and Xeno Trunks arrive in a completely decimated world, one ruined by a powerful and dangerous force. As they search for the being responsible, the Namekian villain Lord Slug makes his presence known with a massively powerful attack launched against the two multiversal heroes. Rather than retaliating with a ki blast of their own, Xeno Gohan begins whistling loudly, which causes Lord Slug a great deal of pain as the villain quickly covers his ears and cries out in agony at the sound. When Xeno Trunks asks Xeno Gohan what is happening, Xeno Gohan explains, “I learned a long time ago that Namekians are weak against whistling!”

The whistling attack Xeno Gohan uses against Lord Slug would also work against King Piccolo as well since he, too, is a powerful Namekian. Whistling is a fairly common skill within human society in both the fictional world of Dragon Ball as well as in real life. Therefore, anyone with that particular skill could conceivably weaken any Namekian they come across even without the other powerful attacks used by the heroes of Dragon Ball. The reason for this is because Namekians have hyper-sensitive hearing, so whistling can cause them a great deal of pain–a surprisingly simple weakness that turns a Namekian’s strength against them in a truly humiliating fashion.

Given this weakness that nearly anyone could exploit, Goku’s victory over King Piccolo definitely seems like overkill given how he literally shot his body through King Piccolo’s when he could have just whistled an annoying tune to take him down. While Namekians are far from the most powerful species within Dragon Ball, with King Piccolo not even close to being the strongest villain Goku ever faced, this revelation makes them seem infinitely weaker since Goku’s first archenemy and every member of that enemy’s race are weakened by whistling–a weakness so simple that even Dragon Ball fans can beat them.