The Groovy Gang were a group of mentally disturbed amateur detectives that travel the world in a van to solve mysteries that may or may not exist. The group consists of the insane, violent-tempered, and self-righteous leader Ted, the weak-willed kidnapping victim Patty, the angry, feminist-extremist lesbian Val, the paranoid, jittery hippie Sonny and the terrifying, possibly possessed dog Groovy. While the Gang purportedly existed to solve mysteries, Ted never seemed to have a clear definition of "mystery", and, in reality, the Gang seemed to make their living by looting the buildings they would break into during their adventures. According to Patty, the gang has been driving to her parent's home for 10 years, suggesting they had been active for that length of time.
- Ted: the clearly disturbed leader of The Groovy Gang. He controls the others with threats both verbally and with a gun. He apparently keeps Patty locked up in a cage and doesn't allow her to see her family or take showers. For some reason, he feels the need to solve mysteries that don't even exist much in the way Hank and Dean sometimes do. He led the gang into the Venture Compound where he was eventually killed by Brock when he got head-butted. Rusty Venture planned to use Ted's corpse to advance his Venturestein project, which he ended up doing by rebirthing Ted into Tedstein, a follower of Venturestein. Based on notorious serial killer Ted Bundy.
- Sonny: he was a hyper-paranoid, unhinged, and downright shaggy member of The Groovy Gang. Sonny is the only person that his talking Great Dane, Groovy, will speak to, much to Sonny's chagrin, as the other members of the Groovy Gang believe that Sonny is merely hallucinating. He frequently begs Groovy to speak to the other members of the Groovy Gang so that they will believe him, but Groovy claims he will only speak to Sonny, as he is chosen to be the "Hand" of "The Master". It is possible that Sonny is an unwitting servant of The Master, but it seems much more likely that he's just a "fucking lunatic". Ted motivates Sonny to participate in the Groovy Gang's adventures by offering him "Groovy Treats," which are prescription pills of some sort (possibly anti-psychotic medication). When this doesn't work, Ted simply threatens to "chain [Sonny] to the back of [his] van and road-haul [him] until [he's] nothing but a pelvis wearing a belt." Sonny, like his Scooby-Doo counterpart Shaggy, is terrified of ghosts and most other things. Sonny and Groovy previously ran into Hank and Dean Venture in a cave in Baja and, in a fit of terror, brutally murdered them and dumped their mutilated corpses into a hole. During the Groovy Gang's second encounter with the Ventures, Sonny encounters Hank and Dean again and, knowing that he had murdered them in the past, becomes convinced that they're ghosts. Later, the Gang stumbled upon Rusty Venture's army of Hank and Dean clone slugs, when they were accosted by a spiritually reborn, rage-fueled Brock Samson. In an extremely short, extremely one-sided battle, Brock broke Ted's arm, fatally wounded Sonny with Ted's handgun, and then head-butted Ted to death, while Groovy was unintentionally strangled by Venturestein, killing him. Rusty Venture planned to use Sonny's corpse to advance his Venturestein project. Rusty later acted on his plans and rebirthed Sonny into Sonnystein a follower of the original Venturestein. Based on serial killer David Berkowitz, a.k.a. "Son of Sam".
- Groovy: he was a Great Dane and the mascot of The Groovy Gang. He is capable of speech, but will only talk to Sonny, claiming to have no interest in speaking to anybody else because only Sonny is chosen by "The Master". Groovy is a parody of Scooby-Doo, but unlike the famous cartoon character, he somewhat speaks more properly. His voice is more Germanic, menacing and demonic, and he often advises Sonny to do terrible things to punish the wicked in the name of The Master. Given that Sonny is a drug-addled, murderous lunatic, it is very probable that he is merely hallucinating Groovy's voice, although Sonny adamantly denies this, claiming, "And this dog fucking talks, man!" Together, Groovy and Sonny had previously brutally murdered Hank and Dean Venture in an underground cavern, and dumped their battered, mutilated corpses into a dark hole. During the Groovy Gang's second encounter with the Venture Family, Rusty Venture's latest unholy abomination, Venturestein, strangled Groovy to death while Brock Samson killed Sonny and Ted. Venturestein later used one of Groovy's feet to make a shoe, planning to give it to a prostitute in exchange for sex. Groovy mentions Sonny being the hand of someone called the "The Master". The only known Venture Bros character called by that is Orpheus's Master. It is possible that Groovy may have been involved with the dark arts, or maybe the Master's underling; it is possible that Groovy is an expy of one of the fierce dogs attending another 'Master' in the famous bad-film Manos: The Hands of Fate . In addition to Scooby-Doo, he is a parody of Harvey, the dog of David Berkowitz's neighbor, who Berkowitz claimed was possessed and compelled him to commit murder (though he later admitted the claim was false).
- Patty: is the quiet and meek beret wearing member of The Groovy Gang. She was apparently kept in a cage at most times by Ted, the leader of the gang. Ted also didn't allow her to shower or see her parents for ten years. Patty along with Val are the only members of The Groovy Gang to survive and escape the Venture Compound. She is based on Patty Hearst, the granddaughter of newspaper mogul William Randolph Hearst and kidnapping victim of the Symbionese Liberation Army, a left-wing paramilitary group.
- Val: she is a chain-smoking, misandrist, pseudo-feminist lesbian and a member of The Groovy Gang. Believing that men were "walking abortions", Val ceaselessly explained her insane misandrist vision to Patty, heedless of Patty's apparent disinterest in the subject. Val also harbored a lesbian attraction for Patty, as evidenced by Val's apparently frequent attempts to grope her, but the infatuation was unreciprocated. Unlike Ted, Patty, and Sonny, Val doesn't seem to operate under the delusion that the Groovy Gang is an amateur sleuthing organization, and while the other members of the gang combed the Venture compound for "clues", Val spent her time searching for valuables that the Gang could loot. Val and Patty are apparently the only surviving members of the Groovy Gang, as Ted, Sonny and Groovy were killed by Brock Samson and Venturestein. She is a parody of Valerie Solanas, a radical feminist and out-of-the-closet lesbian who attempted to kill artist Andy Warhol for refusing to read a screenplay she had written.
- The Groovy Gang is very clearly inspired by the mystery-solving gang in "Scooby-Doo, Where Are You?" However, each member of the Groovy Gang is also based on a famous 20th century maniacs.