The Birth: A villain born in Marvel's golden age, the Lizard became another one of the Spidey villains to be immortalized in history. Spider-Man first came face to face with the Lizard in Amazing Spider-Man #6. He is another one of the Stan Lee and Steve Ditko creations.
Dr. Curt Conners was a surgeon before he lost his right arm in the war. He then went into an in depth study of reptile life and soon became one of the world's leading authorities on reptiles.
He was sure that if certain kinds of lizards could regenerate whole limbs and tails, then using their secret man could also do the same. After months of experimenting, Curt Conners came up with a serum that worked. But it had only been proven on his lab rabbit. Eager to try it out, he drank the entire thing and like his rabbit, he grew back his right limb. But the change didn't stop there. The retile serum caused his skin to form scales and soon his physical transformation into a lizard man took place.
The good doctor tried his best to find out a cure but the transformation dulled his brain and the " I shall take over the world" syndrome grew on him.

The Alter Ego: Curt Conners was a gifted surgeon who went into a war to help his country.He performed "meatball" surgery on wounded GIs, but his arm was injured in a blast and had to be taken off.
Conners had a wife, Martha and a son, Billy. Conners is a family man and can go to any length to save his wife and kid, even as the Lizard. He can easily be called a genius but has hardly any of the eccentricies of the stereo-typed mad scientists. Of course, when he morphs into the Lizard, he sings a different tune.

The Legend: In Amazing Spider-Man #6 we are told of a monster that has been terrorizing the murky swamps of Florida's Everglades. Locals say that it is a giant lizard, and some of them say they've heard it talk. Rumors have it that the creature is bullet proof and has the strength of a dozen bulldozers. Catching the grapevine news, Jonah Jameson decided to advertize a challenge for Spider-Man to defeat the Lizard, a clever ruse to sell papers.
Conviniently, Peter Parker goes along with ol' J.J to Florida to capture the creature on celluloid. After he ditches his eccentric boss, Parker goes to the swaps in his Spidey suit and gets a first hand review of the Lizard.
Spidey found out from Martha about how Dr. Curt Connors had been transformed and he worked on an antidote to help the Lizard. The formula was successful in returning the Lizard into his original self.
Oh yeah, he does turn back into the Lizard a couple o'times after that to resume his task of being a world conquerer. He moved to NYC to work at Peter's university. More convinient too, considering Spidey couldn't go every now and then to face a threat in Florida. In ASM #44, Lizard resurfaces in New York and Spidey makes the usual promises to his wife about curing him. In his battle with Spider-Man, Lizard broke Spidey's web causing him to fall and sprain his arm. The Lizard had sent for a huge consignment of crocodiles, snakes and other reptiles which would serve him in his quest for world domination. But Spidey arrived on the scene and knocked out the Lizard in a refridgerator cart on board a train. He feeds the antidote to him transforming him back into Curt Conners and all is well.
When his wife and son left him, Conners decided to straighten out things. In despair, he transformed back into the grotesque monster and under Calpsyo's voodoo worked for her. As always, Spidey took care of things, causing Lizard to gain his thoughts back. Though the Conners personna was weak, it carried out a plan and cured himself temporarily.
Some time back a huge animalistic Lizard appeared causing everyone to think that the Lizard was back for good. Turned out it was a result of Curt's previous attempts to cure himself. When this imposter came after Curt and his family, Curt was forced to transform back into the Lizard to protect his own. The two of them duked it out resulting in the death of the imposter. But this brought back the Lizard personna in his mind.
The Lizard's latest scheme to take over the world had him affecting the water supply to turn everyone into his mindless slaves, though after Conner's son, Billy, almost became one of these zombies, Spiderman lashed out and attacked The Lizard. After Martha got her share of words in, The Lizard became Conners once again, now begging for help for a cure.
No-one knows when he'll next change back into the monster.
..... The initial rumours about his strength were true, the Lizard possesses amazing strength and power. He was even able to break off one of Spidey's webs, a feat the a few can accomplish. His hide is highly dense, preventing injury from even shotgun bullets. Because of such power, he never uses any weapon in combat. He also possesses power to mentally control any reptile, a power which he's put to his advantage on more than one occasion.

Amazing Spider-Man #6