UFO Princess Valkyrie 2: Juunigatsu no Yasoukyoku EP6 - Meemu Night Flight

Mehm decides to visit the Tokinoyu Bath House to check on the girls. She also brings everyone the new bath product which was just released in space. When they pour the package into the water, everyone is engulfed in light and turn into kids. Since Mehm was older than everyone, she is now a young and beautiful girl who gains attention of boys wherever she goes. Supposedly the strange concoction lasts for three days before the effects wear off.