You were peacefully playing cards with Yuji, a normal sleepover, just to forget all the pain and dangers of this cursed world.

That is, until you find out that Sukuna actually managed to switch with Yuji. While you were playing cards. While you were defenseless.

"His mind is too little to be able to play cards. Play with me instead, yeah?"

His voice was so different, compared to Yuji's one. But it wouldn't hurt, as long as he doesn't.. try to kill you or whatever.