Joker and the crowbar

This subtitle alone is a hint of what is happening in the background – as Johnny Frost takes care of the good doctor, we see one of Joker’s goons being shot in the background. This is not interesting at all (though we do see the blood splattering and further hope for an R-rating). The shot goon is with his back to another, well, background scene. A hidden scene, since there are small explosions and lots of sparkles hiding what is happening in the other room.

Now, we all know that this entire assault on Arkham is a flashback – so we do have a timeframe: sometime when there were still good men in Gotham.
So what is happening in the other room? Well, it is Joker swinging a pipe/crowbar and beating to a pulp someone, who is still hidden (and, as it seems, in a bag). In the comics, who met this horrible fate at the hands of the Joker?

Well, of course, it was a Robin! Killed by the Crown Prince of Crime, he would come back to life via the Lazarus Pit as the new Red Hood!
Head on to the next page for more evidence!
