My first two "waves" of COBRA zombies were based on the special-infected ftome the Left 4 Dead games. Series three brings the freak-type zombies from another excellent zombie game, State of Decay.
This was a fun exercise in just how different a figure can look by rearranging it's own parts. I swapped the thighs and shoulders to change the proportions, then cut up and reshaped the lower legs into a digitigrade formation so he could scramble along on his fingers and toes. Another naked zombie, because they're just more terrifying that way sometimes.
Nom Anor - Head
Sabretooth - Fingers
Grinnah (The Hobbit) - Base Figure