"We keep pushing him down, but he keeps coming back up." — Carl
The Regurgitator was a villain and serves as minor antagonist that was set at high priority at the O.W.C.A. because he was supposedly more evil than Dr. Doofenshmirtz.
After Agent P was assigned to him, Doofenshmirtz was sent a welcome basket from the Agency that came with a letter telling about him being low priority, and so he went to the Regurgitator's lair to try and restore himself to a higher priority again. The Regurgitator gave Doofenshmirtz a form to apply for an 3 year internship at his lair. Doofenshmirtz accepted, and started working. The Regurgitator was also very fast and efficient at capturing his newly assigned agent, Perry the Platypus. Doofenshmirtz, however, began having doubts when the Regurgitator says that he was not going to explain his plan to Perry before getting rid of him. Feeling unappreciated, Doofenshmirtz told him about all the things he made for the Regurgitator, a pair of rocket boots to reach the files in his wall, and a self-destruction system for the lair that was already counting down. It also turned out that Doofenshmirtz also built a release button inside Perry's cage. Perry pressed it, and escaped. He flipped the switch on the tube that Doofenshmirtz entered through, causing it to start sucking upwards, making the Regurgitator get sucked up it, and shot through the building into the sky. Perry put on the rocket boots, grabbed Doofenshmirtz and flew away. The Regurgitator then landed in the O.W.C.A.'s prison.
He was far more efficient in capturing Perry than Doofenshmirtz and probably he would have sent Perry to his doom if were not by Doofenshmirtz actions.
He probably was known by crime-hunters because he was enlisted as "The World's Most Evil Villain" on his own web page.
Before Heinz knows him, he had heard about Doofenshmirtz as the "lunatic of Danville"; once, Doofenshmirtz went to his evil lair to see why he (Doofenshmirtz) has been downgraded to a less evil man and The Regurgitator gave Doofenshmirtz a form to apply for an 3 year internship at his lair. Doofenshmirtz accepted. Doofenshmirtz, however, began having doubts, feeling unappreciated,. It also turned out that Doofenshmirtz also built a release button inside Perry's cage. Perry pressed it, and escaped.
It is stated that he lives in the Quad-State Area. While this is probably just a way to show him being superior to Doofenshmirtz, the Quad-State Area could be around four corners in Utah, Arizona, New Mexico, and Colorado, because of its desert-like appearance.
When he raises his voice in sentences like "I am the Regurgitator!", "The world is my nemesis!", and even "You can start by making a fresh pot of coffee!" (to Dr. Doofenshmirtz), he uses his watch-like device to emulate lightning effects.