There were three different versions of TMNT's 2K3 theme. That does not include the rejected theme song found on the Toys R' Us FoxBox promo CD or Fast Forward's theme. There was the theme everyone was familliar with which spanned the first three seasons. It was changed at the beginning of season four to reflect Shredder's defeat, with Mikey hopping around and saying, "We shredded Shredder!" Other lyrics were changed as well, but that isn't important for this discussion. It stayed that way for fifteen episodes. After that, the cat was out of the bag that Karai was the new Shredder. So, "Prodigal Son" on up featured a theme with Karai saying to "Watch out for Shredder". I hope that answers all of your questions. Peace out, grotesque ganglion... or whatever it was that Uncle Phil used to call you.
