Wizard101 is full of cool mounts in game, but the Arcus Cloud Mount is pretty new and just released this past year I believe (time just flew by in 2013).
I remember sitting around the KingsIsle offices and all the Marketing folks were talking about how awesome this new mount was, and they're totally right. Riding around on a little bed of clouds sparking out lightning is the stuff of genius. GENIUS!
I think there's maybe three mounts you ride like this in game now (flying carpet and surfboard are the other two, yes?), but I just love this thing right now. I need to get my son's character, Kyle Skystaff, one of these because a Storm wizard on a storm cloud is about as perfect as it gets for awesome style points!