Misunderstood

Bella had a granola bar the other day and then wanted another so I let her. As I was giving her the second bar I told her, "This is the last one." A few days later when I asked her what she would like to eat she said, "I want a last one." I couldn't understand what she meant so I asked her to show me. As she pointed at the granola bar box, I remembered what I had said to her the last time she had one. She thought the granola bar was called "Last One".