I refer to our baby as "Snowman." It could very well be "Snow Woman" for all I know, though. (After three girls, I've lost hope of a boy. Lol.)
The reason I call our baby this is because at one of my earlier ultrasounds the baby looked just like a snowman. And it was the first time I saw the baby, so that made it even more special. There was a small circle for the head. Then there was another bigger round circle like for the body. It was odd. If I had pictures, you could really see why I would think this.
So what are you calling your LO these days?