In "What Ever Happened to Baby Brain", Brain actually crosses paths with Welles, who is working as a busboy in a hollywood restaurant, and they find themselves inadvertently yelling in unison, "Things will be different when I take over the world! He is highly intelligent and develops complex plans for global domination using politics, cultural references, and his own inventions toward his goal. He seems coldly unemotional, speaking in a snarky deadpan. In Wakko's Wish , he said to Pinky "We're on our way to fame, fortune and a world that's a better place for all. However, his motives are not pure. In one episode, Brain finds himself hypnotized by a psychologist he had planned to manipulate for one of his schemes, who turns out to be none other than Sigmund Freud.
However, things hit a snag because of a new dance craze which is making people dumb. A White House conference is called to find a solution. Brain is mistakenly invited. Suddenly, a sinister clown steals the speech the Brain was giving. As the mice are leaving, they pursue him and are captured.