Harvey Birdman, Attorney at Law features ex-superhero Harvey T. Birdman of Birdman and the Galaxy Trio as an attorney working for a law firm alongside other cartoon stars from 1960s and 1970s Hanna-Barbera cartoon series. Similarly, Harvey's clients are also primarily composed of characters taken from Hanna-Barbera cartoon series of the same era. Many of Birdman's nemeses featured in his former cartoon series also became attorneys, often representing the opposing side of a given case.
Bandit from Jonny Quest and Scrappy Doo are killed off in the first couple of episodes by Avenger. Their corpses are frequently seen throughout the series as background elements and running gags. There is no gore in the deaths, nor are they on-screen, and their carcasses are completely intact.
In the Race Bannon VS Benton Quest custody battle episode, the two men are portrayed as a pseudo-innuendo gay couple, where in one instance Race uses mild physical force on Benton in an argument about custody of Benton's children.
Harvey sleeps with one of his clients, a Kama Sutra book shows Quick Draw McGraw and Baba Looey in a sex position, it's an adult swim show for crying out loud.
A character named X the Eliminator is a hired assassin-turned superfan of Harvey Birdman. X frequently stalks our protagonist for various reasons (mostly obtaining his crest) but it's always played for laughs. He's the least threatening character and I'd totally go to McDonalds with him and his roomie for some mcnuggies.
A character named Reducto (played by the hilarious Stephen Colbert) appears to suffer from mental illness and frequently breaks into panic and disarray, along with compulsive threats and other tendencies. He has a complete and total mental breakdown on multiple occasions.
An occupied clown car is used at times as a running gag, but only for brief intervals. They never take priority in an episode nor are they purposefully made to be scary-looking.
An episode revolved around the titular character Harvey Birdman potentially having a cancerous mole due to his frequent exposure to the sun in order to regain and maintain his superpowers. This ends up just being a comedic bit and not a fatal circumstance.
A character named Phil Ken Sebben mistakes his daughter, disguised as a superhero, as a potential lover. She is highly uncomfortable with it and thwarts his advances every chance she gets. Whenever she unmasks herself and returns to his side as his recognizable daughter, he does not make any attempt at romance.