Peter Potamus is one of several Hanna-Barbera Funny Animal characters created during the 1950s-1960s Three Shorts period to have his own show. A purple hippopotamus, he's a Half-Dressed Cartoon Animal clad in a yellow pith helmet and a white safari jacket cinched with a belt. Accompanied by his monkey sidekick So-So, Peter explores the world in a time traveling hot air balloon, encountering all sorts of far-fetched and fascinating adventures. Whenever he gets in trouble (as seemingly happens once each episode), Peter uses his devastating "Hippo Hurricane Howler" to blow away his enemies. Daws Butler voiced Peter (using the same Joe E. Brown style voice employed for Lippy the Lion), while the actor who portrayed So-So was Don Messick.
Peter proved more resilient than many other characters of this type. He was a recurring fixture in Harvey Birdman, Attorney at Law, atypically portrayed as a lazy and disreputable (but highly accomplished) lawyer and serial womanizer. The purple hippo also appeared on Yogi's Ark Lark, Yogi's Gang, Yogi's Treasure Hunt, Laff-A-Lympics, and The Good, the Bad, and Huckleberry Hound, among others. Like many of his fellow H-B characters, he's also part of Jellystone!, now an Occidental Otaku, of all things.
- Affectionate Parody:
- "The Reform of Plankenstein" is a take-off on Frankenstein. The Mad Scientist title character gets reformed by the end of the episode, using monster parts to build a merry-go-round for the villagers' enjoyment!
- Robin Hood is parodied in the episode "The Good Hood." Peter and So-So try and fail repeatedly to join Robin's Merry Men, but eventually to convince the Sheriff of Nottingham to defect to Robin's troupe.
- "Monotony on the Bounty" parodies Mutiny on the Bounty. Peter falls from his balloon onto Captain Bligh's ship and gets impressed into service since Bligh's crew has mutinied.
- Romeo and Juliet serves as the basis for "Marriage, Peter Potamus Style." The adventurous hippo manages to give Romeo and Juliet a happy ending when he dispatches the latter's disapproving father with a "Hippo Hurricane Howler." The newlyweds even get to borrow Peter's balloon for their honeymoon!
- The episode "Eager Ogre" sends Peter and So-So back to the world of King Arthur, where they battle the title character at Merlin's request.
- Alliterative Name: Peter Potamus and So-So.
- Amazing Technicolor Wildlife: Peter is a purple hippopotamus.
- Amoral Attorney: In Harvey Birdman, Attorney at Law, Peter undergoes a significant change of character from his earlier 1960s incarnation, becoming a lazy and disreputable (but highly accomplished) lawyer and serial womanizer.
- Bizarro World: One issue of DC Comics' Cartoon Network Presents had the time-travel dial send Peter and So-So to a pyramid-shaped version of Earth, where the inhabitants look and act like the "Bizarro World" featured in older DC universe titles — inhabited by Bizarro versions of other Hanna-Barbera characters (among them: Yogi Bear would rather clean up Jellystone Park than steal picnic baskets, Mr. Peebles does not want to sell Magilla Gorilla, and Wally Gator wants to stay at the zoo).
- Cool Airship: The intrepid hippo and simian live in a hot-air balloon tricked out with a ship instead of a basket underneath. Even better, it's capable of Time Travel.
- Face–Heel Turn: In his 1960s episodes, Peter is hearty, helpful, and friendly — definitely a force for good. By the time of his appearance on Harvey Birdman, Attorney at Law, the purple hippo has become a villainous Amoral Attorney. He's back to being a decent person again in Jellystone!, albeit the town mostly sees him as being annoying because of his obsession with Japanese media (which in turn leaves him desperate for companionship).
- Feuding Families: Peter and So-So get embroiled in a backwoods hillbilly feud in "Courtin' Trouble."
- Fractured Fairy Tale:
- The episode "Fee Fi Fo Fun" sees Peter and So-So tangle with the giant from Jack and the Beanstalk, then later switch sides when it turns out Jack is a conniving thief.
- "Big Red Riding Hood" has Peter substituting for Little Red Riding Hood, the better to deliver goodies to her grandma. The plucky 'potamus dispatches the Big Bad Wolf with his "Hippo Hurricane Howler," even teaching it to Red!
- Funny Animal: While Peter and So-So are respectively a hippopotamus and a monkey, they behave like humans. They are examples of a Half-Dressed Cartoon Animal, walk bipedally, talk intelligibly to humans in English, live aboard a tricked-out hot air balloon, and use human tools.
- Half-Dressed Cartoon Animal: Applies to both of the principal characters.
- Peter wears a white safari jacket and pith helmet, but no pants or shoes.
- So-So wears a blue t-shirt and a purple hat turned stylishly sideways, but no pants or shoes.
- Heterosexual Life-Partners: Peter and So-So form a consistent buddy pair and appear not to have any romantic connection.
- Mad Scientist: The title character in "The Reform of Plankenstein" is an evil genius scientist capable of creating golem-style monsters.
- Ring Around the Collar: The top of Peter's jacket and So-So's t-shirt helped facilitate animation shortcuts, a commonly-seen device in Hanna-Barbera characters of the time.
- Super-Scream: Peter’s secret weapon is his devastating “Hippo Hurricane Howler,” allowing him to blow away his enemies with one huge yell.
- Three Shorts: Peter's show consisted of three brief episodes, with his entry going first.
- Time Travel: Many episodes show the adventuring hippo and monkey head back in time courtesy of their specially equipped hot air balloon. They visit prehistoric times in "Pre-Hysterical Pete," the Middle Ages in "Eager Ogre" and "No Rest for a Pest" and "The Good Hood," Ancient Egypt in "Cleo Trio," The Wild West in "Mask Task" and "Calaboose Caboose" and "Wagon Train Strain," The Golden Age of Piracy in "Hurricane Hippo," and World War One in "Trite Flight," among other destinations.
- The Wild West: "Mask Task," "Calaboose Caboose," and "Wagon Train Strain" are all set in the Old West.