Alan Watts was a human who was part of the geological team in the arctic till he was turned into a Cyberman by a Cybermat.
When the Doctor and Amy open the door to the arctic geological base, Alan was waiting there and already been turned into a Cyberman. He chased the Doctor around whilst Amy thought of a plan to stop him which she did by venting out hot steam killing him. The Doctor then took his swipe card so to further continue into the base.