hmmm....It could be like a evil super sonic. sonic in the game could be turned evil by black doom who thinks hes shadow and knuckles is on a quest to save sonic and at the end to save him the only way to make his spirit free is to kill him

and when you defeat him on the game theres a scene like there is always and it shows sonic rise from super sonics body and then fall on the ground where super sonics body was but has know disapeared and he sonic wakes up