Behold The Future
Brain in a jar, he is evil.
The Brain in a Jar is a truly “cerebral” villain: a disembodied brain kept in a container and sustained by life-support equipment. The Brain is primarily a plotting villain, operating through minions and underlings. However, most Brains also possess various mental powers, ranging from psionic abilities like telepathy and telekinesis to the power to influence electronics over a network or mystical powers, possibly including Possession. The Brain may exult in its current “evolved” state or seek to acquire a new body, perhaps targeting one of the heroes for this “honor”!
The brain belongs to some infamous villain from the past whos name is secret. The “brain” is actually a disembodied intellect, such as an artificial intelligence, a digitized personality, or a spirit lacking a physical body, in which case the “life support” device is some other equipment allowing it to function.
The Brain decides it needs a body to match its magnificent mind, so it comes up with a scheme to kidnap the ideal victim and transplant itself into his or her body. Perhaps the intended victim is a friend or loved one of one of the heroes, or even one of the heroes themselves!