Board Thread:Manga/@comment-27321453-20191108184732/@comment-37493549-20191122140745

I don't think it is transforming the same way other titans do though. Eren's spine literally extended with some weird tendrils then shot out of his severed neck and reconnected to his head before he even started transforming, we've never seen anything like that before. The human body within has always remained in its normal form inside the titan in the past.

It might be some different kind of creation from the paths than a titan. The walls and the war hammer's abilities come from the paths too but they're not titans. This thing's spinal look might be a manifestation of the creature from the tree, who knows. We don't even know if Eren's actually attached and inside it either, we've only assumed that.