Transcription
Iron Man became the Green Goblin as a result of Secret Wars. The remnants of the Marvel Multiverse were recreated on the patchwork planet known as Battleworld. Each realm was based on a different reality, and one of these realms was known as Spider-Island, where the heroes had failed to prevent the Spider-Queen from infecting most of Manhattan with a virus that put the populace under her control. Tony was captured and infected with the virus. The only way to free the infected heroes from the Spider-Queen's control was to inject them with other viruses. So when the remaining heroes rescued Tony, they exposed him to the Goblin serum, created by Norman Osborne, which effectively turned him into the Green Goblin, freeing him from the Spider-Queen's control.
Tony's willpower and inventive nature allowed him to briefly adapt to the situation, even incorporating Green Goblin elements and weaponry into his Iron Man armor. This corrupted Tony played a vital role in giving the heroes an edge against the Spider-Queen, which eventually led to the fall of her regime. However, when the Spider-Queen's forces cornered the resistance, Iron Man elected to stay behind and chose to sacrifice himself to cover others' escape.