** Massive was originally voiced by Creator/MichaelClarkeDuncan, but he is instead voiced by Creator/KevinMichaelRichardson in "The Hunter".
** Mr. Leghorn goes from being voiced by Bill Farmer in "Stop the World, I Want to Get Off" to being voiced by Creator/RobPaulsen in "The Music Villain".
* TalkingToHimself: Tech and Slam, both being voiced by Creator/KevinMichaelRichardson.
** The main characters originally had [[http://www.animatedviews.com/wp-content/uploads/2012/11/Original-Loonatics.jpg different designs]]. The most notable differences include Ace Bunny having noticeable buck teeth and Rev Runner being colored blue instead of red.
** Zadavia was originally named Maxima, as seen in the [[https://www.youtube.com/watch?v=mIIpJPiRjQM teaser]].