A Hat in Time - Moon Jumper NPC
I was hoping that the moon jumper's files would still be around when the editor came out, and, sure enough, not only are the files for his textures, model, animations, and music still around, but I found the file "Hat_NPC_MoonJumper.uc" in the files, which is an entire NPC script for the Moon Jumper. Looking at it right now, there are also files for Tim the Time Lord, Tim's Friend, and Thor the inventor.
FEBRUARY 2018 UPDATE: As of a recent update, the MoonJumper can no longer be spawned in using the command used in this video. However, the NPC's script still exists in the editor, so creating a mod with the script should theoretically allow you to spawn him.