8. Mother Brain – “Metroid”
Disembodied brains have become something of a sci-fi trope over the years, but the “Metroid” series’ most well known villain, Mother Brain, takes the cake. She was first depicted as simply a massive brain contained in a glass jar, delivering psychic orders to her army of Space Pirates. Mother Brain eventually gained a body of her own, even more grotesque and intimidating than a spiked, one-eyed brain, leading to one of the most epic and unforgettable boss battles in classic video game history.