You'll need a blind bag pony.
I've seen them in boxes in the pink toy aisle at most stores.
The trick is...you don't know which pony you are buying!
(I find that squishing the bag, I can easily tell the shape of the pony inside...
so it was easy to find this Fluttershy)
This is where the necklace will hang from, so it helps if it's balanced.
Great gift idea or birthday party favor too!