oh Cid is a regent. I really don't want to say anything else as it could be a spoiler but lets just say at the start he turned into an oglop by his wife (a bug as you will find out) then he becomes a frog cos somebodys potion mixing and eventually becomes human again
don't worry. he changes with Zidanes potion mixing skills. He gets taller but not by much. He doesn't become human again until his wife turns him back during disc 3 just after Esto Gaza (sp?)