In this part Brenda is showing Cinder, Emerald, Mercy, Neo, Raven, and Summer around the base, while Phineas, Ferb, and Donnie are working a special potion in the lab. Unknowing that Ruby found a the potion that she thought it was a drink and drank it.

Later, when the scientist return they saw something that shocked them. They soon got the rest of the team and they too were shocked to see Ruby in her young age. Ruby explained she didn't know how this happened. Brenda then noticed the potion bottle and later explained what happened. Hopefully she, Summer, Taiyang, Raven, Qrow, Raven, Weiss, Blake, and Yang find a older potion so Ruby won't be young forever.

Here's the second idea of this version.