10 Things DC Wants You To Forget About The Penguin
5. He Was The Joker's Sidekick
By the 1960's both the Penguin and the Joker were considered to be Batman's main enemies (thanks in part, no doubt, the the wonderfully hammy performances of Burgess Meredith and Cesar Romero on the Batman TV show) and so they would often appear together.
The comics would frequently feature the two of them either teaming up to commit a heist or trying to outdo each other to prove who was the better criminal. Even more famously, they appeared as the villains during Batman's crossovers with Scooby-Doo (and later in Batman: The Brave and the Bold's pitch perfect parody of those crossovers).
In those cartoons, Joker and Penguin followed the well-trodden path of other Scooby villains and tried to scare the gang by dressing up as monsters... in costumes that they wore over their other costumes.
Despite both characters being popular though, the Joker was still Batman's archenemy. That meant that the Penguin always got the short straw in these team-ups, going along with plans the Joker made and acting as his sidekick.
Considering that a big part of what makes the Penguin an effective villain is his ability to make ingenious and devious plans, the fact that he's happy to follow the schemes of an actual clown puts him in a bit of a bad light.