I don't know if this can still happen, as I didn't try it, but it appears that if you offer to transfer your pet for the pet of someone else, and that other person denies, you get that pet's set
It happened to _mariokart_ earlier today. The items will almost certainly returned, but if someone has an extra shell sitting around, it might be fun to see the sets of people in the beta
post results if you're comfortable doing so
