"Stone Cold" Steve Austin of all people.
Ever since arriving last November, The Shield have targeted, defeated and/or destroyed a lot of people - John Cena, The Rock, Undertaker, Randy Orton, Sheamus, Chris Jericho, Kane, Daniel Bryan, Big Show, Ryback, Brodus Clay, Tensai, 3MB - they even targeted Triple H just recently and I'm sure that's gonna grow into much more of a conflict soon enough (I'm predicting they'll interfere on Brock's behalf at Extreme Rules, but that's another story.) Who else to target? Well, who other than the target of all targets, the Rattlesnake and Bionic Redneck himself.
Imagine Stone Cold Steve Austin has a reason to actually attend a Raw one night. Maybe he's the GM for one night only, like back in June of 2011. Imagine at some point during the show, he has a short confrontation backstage with all three members of The Shield (picture that short confrontation in the backstage halls he had with the NWO at No Way Out 2002) where they tease something happening between them. Let's just say you can feel the tension between them. Then later at the end of the show, he does some sort of promo in the ring (maybe he even has to stunner someone for some reason) and then The Shield's music hits. They surround the ring and maybe Austin even dares them on the mic to come down and get their ass whipped (his words.) They zone in, creep onto the apron slowly as they do, and then quickly come through the ropes and a huge brawl with Austin eurpts. I imagine all of this being awesome, btw.
I see Austin putting up a damn good fight since brawling is pretty much what he did the bulk of his matches during the Attitude Era. Austin fought with the best of them, sometimes one against many (remember him coming in and brawling with all the Alliance guys prior to the Invasion PPV?) I can even see him getting a Stone Cold Stunner in on one of them, likely Ambrose or Rollins. I can see it with either one of them, but I picture it with Rollins better, because it's easier to picture Rollins selling the stunner with his long hair flying back as he takes the stunner. Maybe he gets both Ambrose and Rollins before Reigns takes him down with a harsh clothesline. Either way, they eventually overpower him and destroy him with the triple powerbomb (don't know what else to call it.) This is where the three of them 'toast' a beer to each other and pour much of it over Austin's unconscious body, but unfortunately, WWE doesn't allow beer on the show anymore.
The Shield getting to rub up against Austin and destroy him as well would be awesome.