Someone asked me if I remembered an old movie or show that had something to do with some kind of soup that makes people live forever and some of it ended up on a turtle. I couldn't remember any such movie but I know if there is one out there that the retro crowd would be able to find it.
The only thing I can find close to that is "Tuck Everlasting". From my internet search it's magical spring water that makes you immortal and the girl in the movie gives some to her turtle to make it immortal. Hopefully that helps out.