My son plays with a neighbor of the same age named McKenzie. She is a girls girl complete with princess costumes and Little Mermaid toys. As a result, my son wants Little Mermaid books and such. We were running late for Disney on Ice and I said, "You're going to miss the mermaid" when he pointed to my wife and said "I already have a mermaid. Mama's a mermaid." It melted my wife's heart.
The next day at his school Christmas event, my wife and I were in line getting food when a fellow mom asked if she was a mermaid. My wife did not know what to say and said "not that I know of" and the mom said, "Your son kept saying 'My mom is a mermaid."
It was really sweet that he was so proud of his mama.