The first of many 4'' Arkham City customs, is Mr. Freeze. I know its not perfectly accurate, but I like the turn out!
I used a Duke Acc suit with arms from ironman. I added pieces from Apocalypse and a hair spray capsule, and also added armor pieces from halo figs. The head is a blue star wars guy with the hair removed. The gun is a modified skrull gun. Finally he's topped off with a ice blast from an Iceman minimate.