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There was an episode of... I think Darkwing Duck that involved an empowering ray. The ray had the unfortunate side-effect that its target's head would explode unless they "think of nothing" or "do not think".
At the end, the main bad guy uses the ray to become some kind of super-psychic with massive My Brain Is Big, and he calls himself "a being of pure thought" which gives the protagonists the idea to defeat him by turning the ray on him and asking him difficult questions.
Edited by Medinoc "And as long as a sack of shit is not a good thing to be, chivalry will never die."
Jimmy Neutron also has an episode like that called Sheen's Brain (2004)
If you're potentially misremembering something live-action, Big Trouble in Little China features a villain character's body exploding, with a special focus on his head.
Thanks for the replies. It was definitely an anime not a cartoon because it had anime style voices and animation. I did watch it in the early - mid 90’s but it could have been made earlier and just aired at that time I watched it. It might have been on Sci-Fi channel, we only had a few channels at the time.
hmm i think you might be thinking of an anime called Akira. The main antagonist develops supernatural abilities and eventually his head, then body starts expanding later on.
No Title Anime
Watched in the early - mid 90’s This guy heads grows super large and I believe eventually explodes I think he was a villain He did at least seem to be viewed as a threat by the other characters