The Brain is a villain that wanted to create another World War. G.L.A.D.I.S. and the Brain have the same minds, except Jerry deleted The Brain's evil side in G.L.A.D.I.S. The Brain appeared in one episode, "Evil G.L.A.D.I.S. Much?". He helps Sam, Clover, Alex, and Jerry to return G.L.A.D.I.S back to normal. (Alex accidentally spills cranberry juice on Gladis, she has the same  allergic reaction, turning evil/crazy, as The Brain does when he is exposed to cranberry.)