The Twelfth Beast.
Somehow a cockatrice appeared! The beast is turning further into a climber and a glider. The head crest has extended into the wings, significantly increasing the size of the sail. The back feet have specialized with toes built for climbing and perching, and the front feet have split and become somewhat chameleon-line.
One of my favorites from the exquisite beast tumblr.
Is it just me or does somebody need to do a natural history style background on these?