BC/GA 1, and it was an autopsy of Green Arrow (really Everyman), who Dinah had killed on their wedding night.
It's even more hilarious in context, as right before that scene, Dinah says something like "I can handle this autopsy as long as you don't chop him up and put him in a blender", and Dr. Midnite replies "That's almost exactly what we're planning to do" as Batman revs up the chain saw.