Nina from Angel is always a good one:
https://www.youtube.com/watch?v=PAXCOE5ABjo
A henchwoman in Brave and the Bold gets turned into a hulking cavewoman against her will:
https://www.youtube.com/watch?v=hv0lhEH6arU
Rat-monster-thing TF from Captain Planet,which counts as part of a joining the horde thingy too; since i remember one of the planeteers falls to it:
https://www.youtube.com/watch?v=A6gbN7azsb8
Ogre TF from a japanese videogame:
https://www.youtube.com/watch?v=FZn-3nR75w4