Warning! Spoilers for The Boys comic book series below
Billy Butcher from The Boys has suffered more loss at the hands of Supes than most in the comic book's universe, but his greatest revenge came when he killed a member of the Seven for murdering his dog, Terror. In one of the most tragic movements in the entire series, Butcher finds Terror dead. In response, he unleashes his most cold and calculated revenge on Jack From Jupiter, brutally murdering the Supe for what he did.
In The Boys comic book, Billy Butcher's life changed drastically due to his trauma suffered from supposed Supes. Butcher's wife Becca was sexually assaulted by one of the most powerful Supes in the world and died giving birth to his superpowered offspring. The moment drove Butcher into a personal war against Supes, where he made his mission to take out as many of them as possible, forming The Boys in the act of revenge. However, when one of the few people in his life he still cared about, Terror, his bulldog, was murdered, he made sure to exact his darkest revenge.
In The Boys comic book series, Billy Butcher's dog Terror is his best friend, as he owned the bulldog alongside his late wife, Becca. Butcher has many memories with Becca tied to Terror, so the pup represents one of the few good things left in his life. Butcher often came to Terror's defense against Supes, such as the Crimson Countess, whom The Boys' leader murdered after she threatened his dog. However, after Jack from Jupiter and the Seven meet with Butcher amidst rising tensions, he finds Terror dead in a pile of his blood. Without saying much, he immediately goes after the Supe.
Butcher holds Jack from Jupiter by his neck against a wall while he repeatedly asks the Supe why he killed his dog. He continually stabs Jack over and over again, trying to get answers from him, which he never gets. As Jack's guts literally spill out of his alien body Billy Butcher, clearly in a state of grief, albeit somehow still frighteningly calm, murders him.
Butcher's murder of Jack was one of his tragic moments, as he's so blinded by grief that he keeps stabbing the Supe repeatedly - even after he dies. Terror was one of the last remnants of his old, happy life, so having that taken away from him on top of everything he's already suffered was incredibly sad for the stoic Butcher. The death of Terror and Billy Butcher's subsequent revenge remains one of the most heartbreaking moments of The Boys. Let's hope the TV series doesn't follow suit, otherwise, get your tissues ready.