Yes, that is M.A. Larson. From what I have gathered, he is taking a break this season and is instead writing a children's book. He is not the only stand out writer that has left though, Cindy Morrow was not asked to return and from her Twitter posts was pretty hurt by it. I was pretty crushed at first, but this season has been great for me, with only Bats! being the only real bummer (I mean, it's still a good episode, I just didn't really care for Flutterbat). I kind of feel like Polksy absorbed Larson's talent for this season, I have really liked his episodes so far.