"Skin a crocodile" is an optional mission objective in Sequence 6 / Memory 3: Siege of Charles-towne
Walkthrough[edit]
This is easiest to do on the first crocodile that you encounter just after you start tailing the rowboat. Hit the first crocodile with a Sleep Dart. After that head over to the crocodile and drop into the water. Approach it and hit the prompted button to skin it.