I don't profess to know all of the weird bootlegs out there, but this looks like it could be a one-off sculpt or kitbash of other toys. There don't seem to be any visible lines for articulation. The back spikes are also fairly unique and not something that I've seen before.
For the past decade+, Araki has been using the "写地ア ラーキー" or "Shaki Araki" (sp? maybe meant Shakti?), or "Araki the Photo Devil", as an avatar for himself. It's a customization of an Ecchi sofubi, this one in particular: It's shown up in several books and magazines with his work: As of late, Araki has been publishing a photo diary with a new avatar: I don't know exactly what it's made of or who made it, but it seems to have replaced the customized Ecchi. Maybe sharper eyes can tell whether it's resin, sofvi, or other.
That looks like it! And as @akum6n mentioned, it seems to be a single piece, probably a sculpture. Thank you!
Even after reading the verbiage on the pic and assuming this wasn't an AI image, I also could not help but thinking it looked so much like one, and not just from the graininess. Funny how we have become sensitized to detect it.
