Backstory

So one day in green hill zone while sonic and his friends was having a picnic they notice that dr.eggman wasn’t around to ruined their picnic so they continue on their picnic until there was a ink liquid that was on the tree that is about to land on tails when sonic see it he pushed tail out of the way causing the ink liquid to land on sonic tails was worried and asked sonic if he was ok but the ink liquid took over sonic brain causing sonic to turn into a demonic monster when sonic was a demonic monster he brutally killed tails knuckles and Amy was scared and they tried to run but the monster catches up to them killing them when the other robots that dr.eggman saw this they started trying to beat up that demonic monster causing the monster to have scratches until suddenly sonic turned back to normal and he noticed that there was blood on his hands, and once he saw his friends Bodies he realized that he killed them and he was a terrible friend he ran away and was wanted for the police which causes sonic to wear a cyan scarf and a jacket, and sonic is all alone with no friends and he remembers what he done to his friends..