Can anyone tell me who this villain is and what storyline this scene comes from?
Maybe a strange incarnation of Solomon Grundy?
That's definitely The Ventriloquist and Scarface in the background anyway.
I found these panels here.
They were illustrated by Norm Breyfogle, if that helps.
Major Stacking's answer is great, it really does look like the new Scarecrow. The only thing stopping me from accepting it are the facts that:
A. Since when has Scarecrow been able to pimp slap Batman around?
B. Scarecrow is human. The guy in the panel above is full of bullet holes and has a batarang sticking out of his eye. I don't think a normal human could survive those injuries.