Wow, noone is being very specific (or not being helpful at all, not that I’m saying I’ll do better)
anywho, I would do this effect by filming the actors seperately (I’d do it on a greenscreen, less work, but it could be done on-set)
then you would put the two layers to match up chronologically and matte the top layer (probably the guy getting punched) so that you can see the bottom layer and not see it when it’s going through the guy
the reason I’d do this on a greenscreen is that, without a greenscreen you will have to rotoscope this, which is a pain
of you want more help, I’m not the person to ask because I do not proffess to be good enough to help people with AE, but if you do want to talk to me, send me an email (venom00737@gmail.com)