The proper name of the lovely creature above appears to be “Doom Dragon.” What is also interesting, albeit in a confusing way, is that the images have “101” in their file name (rather than “101b”), where the concept art from “The Picnic” that he published previously had a “104” (rather than “102a”). Either they didn’t pair the episodes as “a” and “b,” used separate numbers, and both episodes moved together by one spot each, or they used the same number for “a” and “b,” and “The Picnic” got promoted later in the development. I wish I knew!
Update: There’s more! He just put up three more images (included above).