DCUO Boss - Robin
Be sure to grab the two missions by the front door. Most of the zone is just working your way through and killing the cops as you go. You come up against a couple of mini-bosses but they really aren't too much trouble. Unleash damage and keep your health up and you'll be solid. In the final room, you face off against Robin in order to free Harley Quinn. You can pretty much ignore the officers in the room as they are too busy with all of the bad guys roaming about and don't do enough damage to care about.
Robin is fairly easy because he is great at announcing his special moves. Every time he tosses out a witty remark, he is getting ready to hurt you so prep your block for these. His spinning staff move does a lot of damage (you actually get a note on the screen when he gets ready to do this one so you can't miss it). If you find that he's really hurting you, just to get out of the way for this one. Either climb/fly up the wall or get back down the stairs until he's done with his staff then get right back into the fray. If you manage to avoid all of the special moves, you might just be able to get through this one without wasting any of your colas!