Jackson, the desert tortoise.
(Sorry about the blurriness. Bad photo)
This was done around 10 years ago when I was first getting into real detail work. The photo reference came from my brother who has a desert tortoises in his backyard in Chandler, Arizona.
I really enjoyed creating the concentric rings in the shell and the scaly skin. It was also a bit more of a challenge success the reference picture was rather small.
The picture hangs in my nephews room and is one of his prized possessions.