Could this be the cake drawing in question? I stumbled upon this while scouring the web for AoSTH production material (because why must l̶o̶w̶l̶y̶ SatAM fans have all the fun?). According to the Tumblr post where I found this, this was used for the AoSTH episode "Sloww Going". I decided to see if any such scene where Sonic gets cake on him appears in the episode, and... Look at that. Sonic's all caked up. Personally, I don't see the "Japanese" in this concept drawing. Just looks like a slightly off-model drawing of DiC Sonic.
Thank you so much for putting together these resources! I was looking for a SatAM Bible/Production Guide on a whim and found these forums because of this post. I hope to put together limited color palettes for artist use from what you've provided. (I figure I'll be digging for Pantone codes for a while, though -- there's so much to go through!) Preservation is a thankless job sometimes, so I want you to know it's appreciated. Thanks again!
Did anyone else take notice of all the new concept art that's been uploaded to the SatAMHistorian X Account? I can't upload them all here since the site's been lurker-proofed. There's some neat stuff here. These definitely need mirrors.
Holy smokes, this is incredible! That Sonic design with the vest and feminine eyelashes almost looks like a fusion between Sonic and Sally, while that Tails design is surprisingly faithful to Yamaguchi's style. Not sure how I feel about that stubby, pear-shaped Robotnik though. However, what fascinates me most is that goblin-esque Snively design. I wonder if it has anything to do with the Fleetway comic's Grimer, as he was originally supposed to be Snively.