I have the sidequest to get a blood sample from the Manbat to learn about it. I have found the creature flying around the city but I can't figure out how to draw blood from it. I have tried throwing Batarangs, remote batarangs, firing the claw at it and gliding next to it. None of those yielded results and the game doesn't give any hints on how to advance the quest.
You have to glide into the Man-Bat in order to get the blood sample. When you hit him, you'll knock him down to the street. A quick cutscene ensues, and you get the blood sample.