Megalomania is a crazy hunger for power and wealth, and a passion for grand schemes. Comic book villains often suffer from megalomania. Their plans are thwarted only by superheroes.
Megalomania comes from the Greek megas ("great") and mania ("madness"). It is a madness of greatness, but not a great kind of madness! Megalomaniacs in history: Alexander the Great, Genghis Khan, Napoleon Bonaparte, Josef Stalin, and maybe even the tycoon Donald Trump.