My brother had one he got from a friend. Apparently he had the joke played on him and thought that it would be funny to pass it on. He told me Indians used it like Novocaine and told me to try chewing a slice for a few seconds.
So I did.
After chewing it for 10 seconds, it took a minute to kick in. It was like the sensation you get when your legs fall completely asleep then you try to walk; pins and needles, but times 10 and it lasted for 20 minutes.
Funny in retrospect, awful at the moment.