Of course, she had to choose a species is able to swap back again. What she want is to experience other species, not living the rest of her life as them. Gazing at the ring, she thought what to be.
First, she considered to be her dog. It would be easy to turn back obviously, as she will still be near by it. But she didn't want it actually. She wanted something more exotic.
"So... pass this..."
While she considering between several possibilities, suddenly, her brother's goldfish caught her eyes. Usually, nobody touch it directly, as it is in its tank. She thought the idea that she can avoid unwanted touch which would make the swap permanent, by swapping with it.
It seemed quite clear, doesn't it? Lucy dipped her finger in the fishtank and lightly touch the goldfish.
In sudden, she watched the goldfish is growing to a human. At the same time, her body was changing to a goldfish. After a second, she became a goldfish on the floor, looking confused wet girl.
But soon, the ring altered the reality. Now Lucy was in her fish tank, and Gwen, who had been a goldfish, was standing in front of her. Gwen was little confused about why she was standing in front of her brother's goldfish for a while, and she walk to her room.
Meanwhile, Lucy was amazed at the ring did work. The only thing she has to do was swimming inside her fish tank freely. At least in her thought.