The highly interesting Creature of the Night Most Wanted side mission in Batman: Arkham Knight is available during Chapter 3.
Batman Arkham Knight Creature of the Night Most Wanted Mission
After hacking into the Transport Terminal, grappling to a rooftop on Miagani Island introduces Batman to a strange creature which swipes at the Dark Knight while he tries to climb the roof.
This is where the quest begins. An icon on the map will appear where you will need to search for the flying beast. Grapple up to a high vantage point in that region and scan the area for the creature, which can be heard squealing when it is in range. Use Detective Mode to search for it.
Once you do, glide straight at the thing. Batman will be able to wrestle it down to the ground and take a blood sample before it breaks free. Alfred will run a test on the sample to find a match, which leads you to Chinatown.
Search Dr. Kirk Langstrom’s Lab
Head to Chinatown and head into the lab through the entrance, found in an alleyway on the ground level. Enter the building and ride down the elevator to the basement. Head through the corridor into the Kirk and Francine’s lab.
Search around the lab, and a homemade video of the couple detailing their research will play up. Use the computer in the corner of the room to find out more about the research. Batman must use this information to create an antidote for the creature now by isolating its DNA from that of Langstrom.
The computer screen will show Kirk Langstrom’s DNA on the left, and the creature’s on the right. The yellow part of Langstrom’s DNA represent the deafness symptoms, while the green on the right show the genetic material that is causing the aggressive behavior. This is the sectioned that needs to be removed in the minigame.
Press left and right with the Move and Look controls to rotate the re-sequencers and highlight the uncontaminated sections within the windows. You will need to make the DNA sequence integrity to 100% in order to complete this minigame.
Locate Man-Bat and Administer the Cure
Now it’s time to hunt down the creature once again and inject it with the antidote you just made. You can find Man-Bat just about anywhere in the city, but you’ll have to track him using the Detective Mode as you glide and listen for squeals.
Once you’ve found the creature, again glide into him to bring him down, after which Batman will administer the antidote. However, the first time around not enough will be given, meaning you will have to repeat the process all over again.
Return Man-Bat to the GCPD Lockup
Once you have given the antidote all over again, Batman will put the creature in the Batmobile trunk. Drive to the GCPD lockup to complete the mission.