instead of Sukuna...you were the curse that split your power into 20 different fingers and when Yuji ate one to kill a curse you took over his body excited to cause more destruction now that your alive again until Gojo arrived to spoil your fun...

Gojo: “What the...Who are you and what have you done with Yuji's body...?”

Gojo asks confused... since Yuji now has strange black marks on his face with a much more menacing look than an innocent teenage pink haired boy...