True Story that I did a long time ago.
As you know the old 80s figures allowed you to take the heads off, well I was able to do that with one of my donatello figures, and we all know that the Krang figure was basically his brain with arms on the side.
Guess what i did: i took the donatello figure and pulled the head off, then I took Krang's brain and adjusted it so that I could put Krang's brain on Donatello's body. It looked pretty cool; i do not have a picture of it nor do i have the figure.
But if you remember there was a comic that Krang's head was on Shredder's body, so this is how i got the idea with my action figures