The cat is out of the bag, though this proverbial "cat" is actually a reptile. That's right, Spider-Man will face off against The Lizard in 2012's Spider-Man reboot. Dr. Curt Connors AKA the Lizard first appeared in 1963's Amazing Spider-Man #6. Connors, obsessed with reptilian limb regeneration inadvertently turned himself into a monster when trying to regrow his own arm with reptile DNA. His arm did grow back.
The Lizard first appeared onscreen in the 1967 Spider-Man animated series as Lizard Man. In this version, Connors used his reptile serum to cure swamp fever rather than to regrow an arm.
A more suave looking Lizard appeared in 1981's Spider-Man animated series, though his alter ego was never shown.
The Lizard would once again rear his scaly head in the 1990's Spider-Man animated series. Once again he was shown wearing the same old white lab coat and purple pants.
MTV's Spider-Man: The New Animated Series presented a much more reptilian, pantless Lizard in 2003.
Although the Lizard never appeared in the first Spider-Man trilogy, Doc Connors was mentioned in the first movie and appeared in parts 2 and 3. It seemed inevitable that the Lizard would appear eventually, though the Vulture was inexplicably scheduled for the canceled Spider-Man 4 rather than the Lizard.
Most recently, the Lizard appeared in the animated Spectacular Spider-Man animated series and the pants were back. As one of Spidey's oldest and most classic foes, I am sure his arrival in the new film will come as welcome news.