The universe of Dragon Ball is full of both powerful characters and silly goofballs who only exist for comic relief. However, as Dragon Ball has been running for so long, the villains have slowly grown in power. This means that the series now is full of characters who, while powerful and dangerous on their first appearance, have slowly dropped down the ladder of threats and have become silly side characters. However, sometimes these comic relief characters show their true power, reminding fans of how powerful and terrifying they actually are.
Beerus is first introduced as a God of Destruction who can wipe out entire planets with ease. In fact, it is said that he once sneezed so hard he obliterated two suns -- he didn't even have to try. During Dragon Ball Super's God of Destruction Beerus Saga, Beerus travels the universe, trying to find the Super Saiyan God he has been seeing in his dreams. When he finds Goku on Earth, Beerus easily defeats Buu, Gotenks, Vegeta, Gohan, Android 18, Piccolo, and Tenshinhan. In an attempt to stop Beerus, Goku enters Super Saiyan God form and fights him, but even this form isn't strong enough to beat the god, and Goku eventually succumbs to exhaustion. While this fight is enough to convince Beerus to spare the Earth, it also shows just how untouchable he is.
However, after this fight, Beerus' true nature is revealed. It turns out that Beerus not only looks like a cat, he also acts a lot like one, spending most of his days sleeping, being grumpy or eating whatever delicious food he or his Guide Angel Attendant, Whis, can get their hands on. While Beerus does threaten to use his power, it is usually an act of dominance. These acts are often used to keep people in line and prevent them from stealing Beerus' food. However, Beerus never really acts on these threats. In fact, when Beerus is well-fed and in a good mood, he is actually pretty friendly, often showing great respect to warriors who impress him, even if they're well below his power level.
However, during the "Future" Trunks saga, we once more see how terrifyingly powerful Beerus is. When Zamasu attempts to kill Gowasu, Whis rewinds time to prevent it. After explaining the situation to Gowasu, Beerus, Goku and Whis corner Zamasu. He tries to attack, but Beerus grabs Zamasu's hand mid-strike and performs his powerful Hakai ability. But the Hakai doesn't just kill Zamasu -- it literally deletes him from existence, painfully and completely.
It is a sobering reminder that Beerus could perform this move at any time, as he executes it with no charge-up time and seemingly no exhaustion afterward. This means that Goku and every other being that has encountered Beerus have to hope and pray that they never anger him, lest they suffer a similar fate. They should also be thankful that Beerus has good self-control as, while he is grumpy and impulsive, he doesn't get pleasure from erasing people on a whim. Because if he did, he could systematically wipe out everyone within a few hours.
It is fascinating to see how Dragon Ball characters change over time. Seeing beings go from all-powerful threats to friendly side-characters is a natural side-effect of the series' massive length. But, just because a character is the butt of jokes, it doesn't mean that their world-destroying powers are totally gone. Beerus is a chilling character because under the grumpy cat facade lies a God of Destruction who could effortlessly destroy anything and anyone without a second thought. Let's hope, for Goku's sake, that Earth food is enough to keep Beerus happy.