Professor Kevin Destructicon was an evil, mad scientist who was a mentor to the evil Heinz Doofenshmirtz some time ago.
Professor Destructicon was the mentor to Dr. Heinz Doofenshmirtz, who apparently learned how to be an evil scientist from him. Destructicon and his student have the similarity that both create schemes that are under-planned and idiotic. However, despite being Doofenshmirtz's mentor, Destructicon is shown to be more idiotic than his student, since his last scheme was to try setting fire to the sun (which was redundant because the sun was already made of fire, as Doofenshmirtz pointed out, "Dude, you really gotta let that one go, it's a ball of fire, it makes no sense."). Unfortunately, he was captured in the midst of this plan. Before he was hauled away to prison, Destructicon told Doofenshmirtz to prevent anyone from discovering his evil lair and all of its secrets by setting fire to the sun. But when Doofenshmritz pointed out the flaw again, Destructicion told Doofenshmirtz to just destroy his evil lair instead with his Disinitivaporator.
While Doofenshmirtz was trying to do as Destructicon requested, he was stopped by Agent P, who put the Disinitivaporator onto Doof's ship. After a fight, Doofenshmirtz manages to cast Perry and the device off the ship before making a clean escape, and Perry is forced to let him go. The device then fell onto Phineas Flynn's haunted house, destroying it. Destructicon's lair is now presumably untouched and abandoned again.
Destructicon's plan to set fire to the sun may be seen as idiotic and redundant at first, as most people believe that the Sun is a ball of fire, but technically it is not. The Sun creates all of its heat and light via nuclear fusion, which is an atomic reaction, rather than by burning and creating fire through combustion, which is a chemical reaction.