Not on screen, it's more of an implied scenario.



I'm gonna assume that you know the endings already? Well just in case anyway, I'll leave this [spoiler warning] here:







The photo at the end of post-genocide pacifist run implies Chara took over Frisk and killed everyone, so if Chara visited Asriel (as you can at the end of any pacifist run), it wouldn't be surprising if Chara killed him there too.