Sam Raimi's Spider-Man trilogy had been carefully setting up the Lizard - but unfortunately, Spider-Man 4 was canceled, and the build-up never paid off. Spider-Man has one of the most well-developed rogues' galleries in comics, second only to Batman, and as a result the films have had a lot of bad guys to choose from.
Director Sam Raimi had long been interested in the character of the Lizard, with concept art suggesting he initially considered him as the villain of 2004's Spider-Man 2. Raimi returned to the idea of the Lizard when developing Spider-Man 4, although in interviews he did also mention characters as diverse as Mysterio and the Vulture. In the end, Spider-Man 4 was canceled by Sony when Raimi withdrew from the project, and Marc Webb was placed in charge of a relaunch, The Amazing Spider-Man.
It was something of a shame, given Sam Raimi had been building up to the Lizard for years. There was a throwaway reference to Dr. Curt Connors in 2002's Spider-Man, and he then made his big-screen debut in 2004's Spider-Man 2, played by Dylan Baker. Connors was one of Peter Parker's lecturers, impressed by his answer to a difficult question, but generally concerned about his student's tardiness. He returned again in 2007's Spider-Man 3, this time acting as a scientific consultant for Peter; Connors took on the role of Reed Richards in the comic book story of the Venom symbiote costume, helping Peter understand just what he was dealing with.
This was an entirely comic-book-accurate role for Dr. Connors, who in Marvel Comics had served as both a lecturer and a scientific adviser to Peter Parker/Spider-Man. Crucially, Raimi's Spider-Man movies introduced Curt Connors as an amputee, foreshadowing his experimentation with Lizard DNA to regenerate his right arm.
In an interview with IGN back in 2007, Baker revealed that Spider-Man 4 was supposed to continue this comic-inspired trajectory. "Well, I would say I'm still the guy that Peter Parker has to come to when he has questions," he explained. "Scientific questions. And I try to help him out." He didn't give any indication whether or not the Lizard would be part of Spider-Man 4, but insisted it was coming. "I'll be trying to get on the Lizard costume when I'm 80," Baker quipped. Concept art for the movie suggests it might have happened a lot sooner than Baker was suggesting, of course.
The cancellation of Spider-Man 4 sadly meant there was never any payoff for all this build-up. Ironically, Marc Webb chose to make the Lizard the first villain of his Amazing Spider-Man films, casting Rhys Ifans for the role. It remains to be seen whether or not Marvel Studios will eventually choose to do their own version of the Lizard as part of the MCU; so far, they've avoided repeating any characters who've appeared on the big screen before, but it's surely only a matter of time.
