Mint Green with Light Blue baby is a fanmade Sing-a-ma-jig Duet. The big one is Mint Green, has teal hair, the same ears as the Lemon Sing-a-ma-jig, rectangle eyes that are colored the same way as the Mint Green Sing-a-ma-jig and the fanmade Sky Blue one, a yellow nose, a pink mouth, the same hand pose as the big one from the Red duet, and the same feet as the yellow "Tutti Frutti" Sing-a-ma-jig. The little one is light blue, has the same ears as the little one from the Purple duet, black rectangle eyes, a nose that is colored the same way as the nose of the Light Blue Sing-a-ma-jig, a pink mouth, the same hands as the little one from the Gold duet and the same feet as the little one from the Plum duet. This duet sings "I've Been Working on the Railroad" and has the same voices as the Gold duet except that this time, the little one signs on, enters song mode and signs off in the same voice as the little one from the Plum duet.
This is there sign on, song mode and sign off
Both: Hello (At the same time)
Both: Song (Big one first and then little one)
Both: Bye Bye!