Bing Bong and Old Bunny

Yesterday my daughter was reading a Disney's Inside Out book. She said her second favorite character was Bing Bong. At first I was confused at what emotion she was trying to pronounce, so I had her spell it.
B-I-N-G-B-O
Oh, Bing Bong
That's what I said
I know but I thought you were saying an emotion.

I then told them Bing Bong made me sad. They asked why?
Because I'm a mom and it means kids grow up.
Joshy doesn't care about Old Bunny anymore. Which is good and fine because kids grow up but it also makes mamas sad. Just like the day you (Nattie) gave away all your baby dolls.
She replied, well that's because I like different dolls better. I said it's because you grew up. But at least we still have Pink Baby.
Oh, that's because Ikey likes her.
(Silently; no that's because this momma has to let her babies grow up but she can't part with Old Bunny or Pink Baby)
And then I'm driving my car home (we were in the car for this conversation) trying not to cry about poor forgotten Old Bunny.

Then I thought I'm not sure my two little boys have one toy they love above the rest.

Poor old bunny...
Just like Bing Bong, I think he's vanished from my 10 years old's memories.

PS I know Bing Bong was imaginary unlike my children's toys, but I have also read singletons are more likely to have imaginary friends.