Selina woke up, and stretched like a cat. Actually, it wasn't "like a cat", it was 'as a cat". She found that everything in her room, including her bed had gotten bigger. Soon, she noticed she had gotten smaller. Finally she looked herself and saw her black housecat, Cleo wearing the necklace.
"Is this is my hand?...or paw?" Selina "meowed", looking Cleo's (or her) paw covered with black fur.
"Uh, that's a tail and... Aww, I think I became Cleo. It's probably because of that necklace." She meowed again.
She touched her neck with her paw. Fortunately, the necklace was still around "her" neck. She carefully took it off.
Suddenly, she found herself lying on the floor. Cleo was next to her, holding the necklace with her paw. Selina took the necklace from the confused Cleo, wearing it, and said "Then, I sure this necklace is the reason. But how this changed me?"
After completely wearing the necklaces but nothing happened, she decided to do something to check which action turned her into a cat. She started it by touching Cleo, and she was right. As soon as her hand touched Cleo, after a short flash, she found herself to be her cat again.
She took off her necklace and came back to normal, amazed at her ability to "possess" any cat by just touching.