We reported in June that the Green Goblin will make an appearance during the final battle of The Amazing Spider-Man 2, but it is actually Harry Osborn who will turn into the villain, instead of his father. Since Norman is on his "last legs," isn't known how the character will fit into The Amazing Spider-Man 3 or The Amazing Spider-Man 4 storylines, although it will likely have something to do with handing his Oscorp company over to his son.
This sequel is taking a major departure from Sam Raimi's original Spider-Man, where Norman Osborn was the Green Goblin (Willem Dafoe) before being killed by Spider-Man (Tobey Maguire), leading Harry (James Franco) to continue his father's evil legacy.
The Amazing Spider-Man 2 was released May 2nd, 2014 and stars Andrew Garfield, Emma Stone, Jamie Foxx, Dane DeHaan, Colm Feore, Felicity Jones, Paul Giamatti, Sally Field. The film is directed by Marc Webb.