Sun and Moon were in Parts&Service, about to get updated, when you stumbled across some old prototypes..

Immediately, without hesitation, you grabbed the prototypes, set them up, and transferred the CPU, programming, and memories into the new prototypes, which took awhile.

But, eventually that while was over, and they powered on.

Moondrop was now a fluffy cat version of himself, and Sundrop, and fluffy golden retriever version of himself.