Imagine this, Diamond Head, the invulnerable brick faces a pack of Hells Angels. One take a mighty swing at Diamond Head and breaks his fist. The others run.
How can we simulate this?
I think one mechanism would be a variant of the rules on Movethorough.
If the attacker does no body or stun or knockback, the attacker takes full damage from his own melee attack. If the attacker is using a melee weapon, then the weapon takes the full damage, and the attacker takes 1/2 the stun.
If hit locations are used, the striking part takes the damage.
Why only for Hay Makers? Well this is to simulate that most strikes are not done with so much force to hurt the assailant.
This could also work for inanimate objects. That would prevent normals from busting their way out of brick prisons (by pushing and haymakering until they rolled enough damage to break out), they would more likely knock themselves out.
So what do you think?