The entity is a demonic spirit inhabiting a pirated copy of Sonic Mania, owned by Y/N and their deceased friend. The aforementioned friend was transferred into Tails in the game, and got possessed by the spirit. Tails is now a simple yellow fox with red shoes, white gloves, two tails and bulgy eyes and lacking a mouth. In phase 2, Tails gain a melting, demented form, eyes drooped. In its final form, it becomes a desaturated, lanky, slender version of Tails, eyes black and hollow and limbs bony.