I believe Shivering Jemmy's appearance on Young Justice is the season 4 (season 4 is called Phantoms) Zatanna episodes. These begin with "Odnu" and end with "Kaerb Ym Traeh!" On the podcast, they mentioned Shivering Jemmy being in a Young Justice movie. Were they referring to this arc on the series? I don't want to say much more without giving anything away.