A8 isnt really in my range here since i wouldnt be 3 betting it. If I don't have the top of my range on turn/river im probably not double barrelling. Im somewhat likely to call a river shove a little wider in this spot because I just don't know what he is flatting pre, then calling my 3bet with. It felt bluffy when he shoved. I figured most likely hands he could concievably have given a flat,Call3bet,x/c flop,x/c turn line was like 77,99,TT which he then decided to randomly turn in to a bluff on river or like JTs,QJs,KJs. Obviously Im never folding my hand here, but I also doubt im folding like AA, KK, QQ and idk what else he could really be putting in my range at this point. I 3bet pre, CBet in to a multi way pot, double barreled turn... like most everything he could fold me off of at this point is no longer in my range because i wouldnt double barrel it with no flush draws or realistic straight draws for a 3bet range on board. Maybe I would take this line with like TT or 99 and consider a fold but there really isnt much else in my range. So I think this is actually a pretty bad bluff. Yes, we have the top of our range here, but i think in this spot our range is so strong hes only ever getting folds from like the bottom 20-30% of our hands. I dont think an overbet shove on river that gets through 20-30% of the time is ever a good play.