With the Amazing Spider-Man just around the corner I thought I'd write an article about the main villain, namely Dr. Curt Connors and his DC counterpart, Killer Crock (Waylon Jones), to see what differences in character are there, despite the fact that they both obviously address the same issue, namely the animal within Man.
First, lets look at the Lizard. A gifted US military surgeon, friend and teacher to Peter Parker, Dr. Connors loses his arm while trying to perform emergency battlefield surgery. He then became obsessed with the reptiles' ability to regrow lost limbs, notably their tail. Developing a serum that mixed reptilian DNA with already pre-existing genetic codes, he grew back his arm but also transformed into a 6 ft. tall lizard. While this obviously represents an emotional challenge to Spider-Man, since he knows the creature is still his friend (at least while he's calm and composed) and does not intend to hurt Dr. Connors, it also plays into the Jekyll & Hyde story with the twist that the creature can excuse anything it does because it is not always intelligent (interpretations vary) enough to distinguish between right and wrong, as only the laws of nature seem to apply, or so the creature claims.
I, however, have a problem with the Lizard's world domination schemes because it does not spring from Connors character. He is a very kind, if obsessive, man who wanted to heal himself and only made his condition worse. One can try to think about what may happen if he ever attempts to cure himself of the Lizard. Might it actually make his situation even more unbearable, as he does not seem to know what is good for him. The other thing I cannot overlook is the fact that the changes in his personality, while initiated by his desire to regrow his arm, are entirely due to the serum he drinks. So the important changes come from outside, while the doctor gave the go-ahead, so to speak, which makes him no more evil than Dr. Jekyll in Stevenson's story. The Lizard's goals vary, depending on what aspect of the character the writers choose to emphasize while Dr. Connors constantly tries to get rid of the monster inside him. This makes for an interesting villain with the only flaw being that the bad changes do not come from inside but from the outside.
Now, lets get to Killer Croc, shall we? The character itself was spawned 20 years after its Marvel counterpart, which probably some people will have intepreted as meaning that he is a rip-off of The Lizard. He isn't. Waylon Jones was born with a genetic disease (avatism/epidermolytic hyperkeratosis/skin cancer) that gives him the appearance of a man with reptilian scales. Hated and constantly mocked by his aunt for his appearance he grows resentful and kills her. He used to be presented as a smarter character than people give him credit for today but in later years people have chosen to represent him as a dumb crocodile. While I have no problem with that it defeats the purpose of having Batman fight more plausible villains like Two-face or the Joker if you have a villain that looks like a huge crocodile.
The best interpretations of the character are undoubtedly in "Broken City" and the "Joker" graphic novel, in which he is basically human looking but with sharp teeth and a cannibalistic streak. The reason I personally prefer him to the Lizard is because Croc's whole issue is that he despises his appearance and lashes out at other people because of that. Yet, by becoming violent he becomes as ugly on the inside as he is on the outside, which might be tragic and it makes us understand why batman cares so much about reforming his opponents because he rocognises their private pain that they then need to act out publicly. Croc plays well into batman's animalistic aspect and is a mirror to our hero because Batman could just as easily become a similar animal, driven by rage and violence. If batman can defeat the urge to injure people to get revenge then he'll be the better man. Croc wants to get even, Batman wants justice for everyone. The difference here, however, is that batman had a choice, whereas you cannot choose yor own appearance and there'll always be someone to mock you, which seemingly makes Croc's rehabilitation harder, as envy, loneliness and alienation dictate his life. Batman could become Batman because the murder of his parents was a direct assault against him, whereas discrimination is much more subtle and it can be based on race, sex, and of course, appearance and apart from trying to change cultural perceptions there is not much a single individual could do. Those are very interesting concepts to explore with the only problem being that Croc sometimes looks too much like a big, stupid animal for us to feel empathy with him.
In conclusion, both reptiles are great but if I had to choose one I'd go for Killer Croc because he's the social outcast who got there because of his own choices, whereas The Lizard is someone who became what he was because of a serum he drank to grow back his arm. I always find character flaws that influence the character's behaviour to be much more interesting than plot elements that create an interesting situation because, of course, at some point you'd think that Connors would find a cure for his condition, whereas an embittered person who's angry at the whole world might actually never change because they do not want to recognize the error of their own ways and at some point they just find it more comfortable to be the victim. Dr. Connors is a good person but his transformation seems too similar to the Hulk (obviously because his emotions make him transform)for me to get too excited about it and the Lizard's schemes seem to go overboard for me (but that's just me). I recognise that others might have a different opinion on these issues and their preferences may therefore vary. there's enough space fr two Lizard-men in comicbooks and both have their different strenghts and weaknesses as far as character development goes.