You see Nightmare sans grab killers soul that is currently shaped into a heart and turn it back to the usual circle you see on his chest

Dust:”…” Horror:”…” Cross:”..Is that a normal thing that happens?…” Horror:”yeah… you’ll get used to seeing it…” Dust:Dust walks away

A few hours later killer comes out of his room and it looks like he’s all healed up after the incident

You are talking with Horror and Cross when you all see him come out Killer:”hey guys! Heh” Everyone stares at him Killer:”uhh.. what’s with the looks?”