A Pethel Smash is when someone getting attacked uses a chair to defend oneself.
In most cases, thee dreaded "Pethel Smash" results in lose of teeth, severe head trauma and possible vegetable state.
I.E.
Friend 1:"Dude! Did you see Dan's face?"
Friend 2:"Yeah man, He got fucking Pethel Smashed like a mofo."
Puddi:"Poor guy."