Ah, the big bad Bat-Guy. I knew you'd "ketchup" to me sooner or later. How I've "relished" this meeting. You, the dynamic Dark Knight, versus me, the conceptual Condiment King! Let's see if you can "cut the mustard".
~ Condiment King's infamous encounter with Batman
The Condiment King is a minor antagonist towards the superhero Batman, as well as Robin and Batgirl. He was originally created as a joke villain who appeared in Batman: The Animated Series, but was later adapted into the comics as well. Although his origins differ in both depictions, he is universally portrayed as a dimwitted criminal who uses condiment-themed weaponry.
Batman: The Animated Series
In Batman the Animated Series, the Condiment King was a stand up comedian named Buddy Standler, who judged an annual stand-up comedy competition. He and his fellow judges rejected a comedian named Shecky Rimshot, who was really the Joker using an alias. A year later, Buddy took up the "Condiment King" alias and used ketchup and mustard sprayers to hold up a popular restaurant. After escaping with the customer's money and jewels, Buddy was quickly defeated by Batman, being hospitalized in the process. It was later revealed that the Condiment King, along with the other strange "villains", were brainwashed by the Joker using Mad Hatter's mind control technology, which resulted in him and the other two being freed of all criminal charges.
Comic Book History
This Condiment King's real name was Mitchell Mayo, an obvious pun on mayonaise. He was defeated repeatedly by Batgirl, Robin, Black Canary, and Blue Beetle. Like the television version he was very weak and was more or less a comic relief character. He eventually became one of the many loser villains who joined General Immortus' army. He along with several villains got power upgrades. His ketchup and mustard sprayers now shot corrosive acids. He is killed however by his team mate Human Flame by being choked to death with a ketchup bottle. Mitchell Mayo has since been revived during DC Rebirth and appeared as one of the villains quickly defeated by Batman and Catwoman.
The LEGO Batman Movie
The Condiment King appears as an ally of the Joker in the 2017 LEGO Batman Movie. After Joker reveals that the Condiment King is one of his allies, he assures the pilot he is talking to that Condiment King is real and "might be worth a Google". Towards the end of the film, Condiment King, along with Joker's other former allies, team up with Batman, Robin, Batgirl and Alfred to stop Joker and the Phantom Zone Criminals.
Tim Drake (during his time as Robin) appears to consider Condiment King as a marginally dangerous threat because despite how hilariously harmless his gimmicks seem to be, they can still be problematic to those who have allergies or got sauce in their eyes (which could lead to blindness).