Megabyte is a virus bent on ruling Mainframe with an iron fist, with ambitions to change it to Megaframe. A villain with no sense of morality, programmed to infect and backstab anyone who dares trust him, he is a seemingly unstoppable force to be reckoned with.
Tony Jay is, hands down, Megabyte. His deep and rich baritone voice is absolutely perfect for this maniacal villain that taunts the heroes with their tragedies that he inflicts on them, playing off his nasty snarling tone with such elegance. What I'm saying is that Tony Jay was born to play villains and Megabyte is no exception.
In 2018, Megabyte was played by Timothy E. Brummund, due to Tony Jay's death a decade earlier. Timothy gets the evil baritone voice down, but there's less of presence of dread with Tim. It just feels like a Megabyte impression (or a Tom Kane impression) than the real deal. Still, that's trying to live up to Tony Jay in general.