This is a fanmade Christmas Sing-a-ma-jig duet. The big one looks just like the Snowman Sing-a-ma-jig, but the only difference is that its mouth is colored the same way as the mouth of the big one from the Plum duet. The snow baby is silver and looks just like the little one from the Purple duet except that its ears are just like the Snowman's ears, and it has an orange nose and a pink mouth (just like the individual Snowman). They sing "Jingle Bells".
Here are what their voices sound like.
Big One: Easter Bunny
Little One: Snowman
Here is how they sign on, go to song mode and sign off.
Sign On: Big One: "Hi There!" Snow Baby: "Hello!"
Song Mode: Both: "Song!"
Sign Off: Big One: "Merry Christmas!" Snow Baby: "Bye Bye!"