When we talk about series that have defined adult animation, the same few shows come up again and again — The Simpsons, South Park, and Family Guy. Perhaps if you’re specifically discussing the creation of Adult Swim or the rise of the sadcom, Space Ghost: Coast to Coast or BoJack Horseman may be added to that list. However, there is one series that is almost continuously ignored despite being the self-deprecating, meta, and serialized blueprint for today’s adult animation: The Venture Bros.

Because Season Six of the series has recently been added to Hulu, it’s worth taking a moment to appreciate The Venture Bros. past. Since its 2004 premiere, the series has always been an odd show. Half comedy, half serious action-adventure series, the comedy follows Hank and Dean Venture, two sweet but aggressively incompetent twin brothers as they go on adventures with their grossly insecure super scientist father (James Urbaniak) and the family’s bodyguard, Brock (Patrick Warburton). It’s essentially a grosser, more vulgar, more dramatic, and funnier version of Johnny Quest that’s unafraid to show blood or delve into depression. It’s also a series that has largely helped define Adult Swim and current animation’s confusing tone.

Adult Swim is often a difficult network to root for. When the offbeat late night channel misses the mark, the results can be undeniably offensive, and they miss that mark often. However, when the network’s programming is at its quirky best, it’s really something special. Adult Swim delights in the bizarre and unexplainable, but it’s often these nebulous concepts that weirdly carry a note of truth to them. How else could you explain the cult success of Took Many Cooks or Metalocalypse? Sure, it’s a weird network that embraces weird shows, but at the center of those shows, buried under bloody concerts and cringe-worthy penis jokes, is often a profound statement about the world. That’s the line this winking show about beautiful failure has always played with.

The Venture Bros., which has recently completed its six season, has always been a show about failure, and you can tell. Though the tone and style of the series is based on old Hanna-Barbera cartoons, very few characters possess the self-assured confidence that used to define these shows. The handful who do possess this confidence, Hank (Christopher McCulloch) and Dean (Michael Sinterniklaas), are laughably pathetic. When you really think about it, The Venture Bros. is a cruel show, one that delves into the life a father who will never reach the level of perfection he has envisioned for himself and his two sons, who are and always will be a constant source of disappointment. Event the Ventures’ arch enemy, The Monarch (McCulloch) is an insecure sham of a super villain compared to the evil foes we’ve grown accustomed to. Not a single character on this series is even close to healthy or well adjusted, but their intensely human pain is effectively played for laughs.

Years before it was the cool norm, Christopher McCulloch’s uncompromising series paved the way for more heartfelt adult cartoons. When Hank and Dean first died in Season One, that hurt. It was painful to watch a mournful Dr. Venture run around the world, avoiding his own grief and the reality tied to it. Now, over a decade after the show’s Season Two premiere, animated sadcoms have become the norm. Both Rick and Morty and BoJack Horseman have been praised for their skill when it comes to balancing sorrow with comedy, and even children-focused series like Steven Universe dwell in pointedly dark moments. These series are dark, not as an excuse to make fun of darkness, but as a mechanism to explore humanity. The Venture Bros. was just the show that set that high bar.

The Venture Bros. was also one of the few early adult animated comedies to play with serialization, experimenting with continuity and meta references long before Archer or more recently South Park. Since its first episode, The Venture Bros. has devoted itself to redefining the world of its genre all the while by paying homage to its past. After all, this was one of the first shows that was released online in 2006, but it’s also one of the few running series that’s traditionally animated.

The Venture family’s contributions to the worlds of animation and television aren’t loud or showy like other series. They’re quiet, pointed, and painful to look at, but they last. There’s a sort of understated give and take to The Venture Bros.’ subtle place in our television landscape that aligns comfortably with this increasingly heart-wrenching comedy. Of course we wouldn’t see the successes of this muted but revolutionary show about failure. That would completely miss the point.

Stream 'The Venture Bros.' on Hulu