Red coins adorn locations in stages in the Challenge Mode.
Sometimes multi-coin blocks will have them, other times blocks with nothing but a coin in them will now have a red coin. Explore and find them!
As stated, Yoshi makes an appearance here too!
He even shows up for the points tally at the end! How cute.
I love this little Fortune Teller mode. There's something about it that's just so charming.
It even has some gameplay ramifications if you're willing to hedge your bets!