7. Killer Croc
Killer Croc is a character who has gone through numerous redesigns since his first appearance in 1983. Known formerly as Weylon Jones, Croc was originally depicted as a strong man with a skin condition, covering his body in green/gray scales. Over the years, he has become larger and seems to have grown a tail and snout, making him look more reptile than human.
Why we shouldn't expect them: I personally hope he never makes in the film business. Even when Croc appeared in the beloved Batman: The Animated Series, he never won me over. I find Croc to be a boring, generic villain and I don't think seeing him on-screen would change that for me. And while this might not be fair, when comparing him to Spider-Man's Lizard, Croc pales in comparison. At least there's an interesting father-son/mentor-student struggle there.