As a kid I always noticed the striking resemblance between Professor Utonium and Samurai Jack and thought "it'd be so cool if they where the same people." And they are! Just in different dimensions.
I shall explain. Here we go.
So in the Samurai Jack dimension, Jack's dad never defeated Aku so Jack could never become a scientist like he wanted so he could never create the Powerpuff Girls.
In Utonium's dimension, Aku was defeated by Jack's dad and was sealed into the sword. Chemical X is actually Aku in a sludge like form. Buttercup is his angry side, Bubbles is his secret soft side and Blossom is his Leadership side.
Don't believe me? Look at this
Believe me now? We also now know Prof. Utonium's first and last name: Jack Utonium
Thank you for reading!