BeddyByes S01E12 - Mystery Song

MeMo and BaBa hear a beautiful sound and wonder where it's coming from. They head to the Play Tree, where they choose some pan pipes to play with. One of the pipes sounds like the beautiful sound, and when they play that note, the sound replies. They don't find the source at Yummy Time, although they hear the sound again. On the Lullaby Lake, they discover that Elewhale is making the lovely noise.