When Julian was a toddler, he had a couple of rubber ducks that he played with a lot in the bathtub. One had a hat, and Julian named it Cookerduck. Apparently we were at a restaurant at some point where the "cookers" had white chefs hats, and he made the connection.
In addition to Cookerduck, Julian had another rubber duck that he used to pour water on top of and called Showerduck. Jo made up a song, "Showerduck and Cookerduck, da-da, da-da, da-da, da-da..." It was very popular.

As time went by, Showerduck and Cookerduck became part of our standard household vocabulary. When Yuko stayed with us for a few months, she made up another duck song, this time about Luckyduck, "Julian's a lucky duck, lucky duck, lucky duck. Julian's a lucky duck, he's a lucky duck, HEY!" She even subsequently wrote a book about the Luckyducks. Other ducks came and went but didn't stick.

Before the ducks, another term that was standard household vocabulary was "snoozer." Jo was a "major snoozer" for many years before Julian and Dylan came along. So, it was only natural that we would start referring to Julian as a snoozerduck when he konked out. He wasn't very happy with the moniker at first and would say, "I'm not a duck" and "don't call me that." So we stopped using it for a while, but it resurfaced when it became apparent that Dylan was also a snoozerduck. Now we have a whole family of snoozerducks. Here are a few examples from around the time we picked "snoozerduck" for our domain name (fall 2002):

Are those snoozerducks, or what?