If, in the wake of Norman Osborn's reappearance, you have heard anyone complain that he can't be alive because the Green Goblin was a member of the Legion of the Unliving in Avengers Annual #16 (1987), and you thought "what the heck is the deal with that?".... here's what it's all about.
In a story that began in The West Coast Avengers Annual #2, a whole boatload of Avengers, along with the Silver Surfer, get involved in a scheme concocted by the Elders of the Universe. The being known as the Grandmaster has a plan to conquer the personification of Death, using "her" power to create a new universe with a new big bang. His "brother", the Collector is aiding him by feigning opposition. The whole magilla begins with the Grandmaster arranging the deaths of the East Coast Avengers (Thor, the Black Knight, Captain America, She-Hulk, Captain Marvel II, and Dr. Druid, at this time). The West Coasters (Hawkeye, Iron Man, Mockingbird, Wonder Man, Moon Knight, Espirita, Hank Pym, and Tigra) allow the Collector to kill them so that they can battle the Grandmaster in the afterlife. But, instead, the two Elders con the two groups of Avengers into fighting each other until the Grandmaster succeeds in capturing Death.
Eventually all of the Avengers unite to try to stop the Grandmaster's "life-bombs" from creating the new big bang. The Grandmaster responds by creating the Legion of the Unliving... "former friends and foemen of yours whom I've selected from within the realm of death!" The Legion consists of Captain Marvel I, Bucky Barnes, Nighthawk, the Swordsman, the Executioner, Terrax the Tamer and others... including the Green Goblin! The Goblin teams up with Marvel I and Drax the Destroyer to battle Marvel II, She-Hulk, Moon Knight, and Tigra.
The fight begins with Gobby using his glider to swoop down on Moon Knight. Moony evades Gobby's pumpkin bomb, then punches ol' Greeny right in the puss. The Goblin responds with hallucinogenic gas. This disorients Moony enough for Gobby to plaster him with a finger blast. He then teams up with Marvel I and Drax (who have defeated She-Hulk and Tigra) to blast Marvel II into oblivion.
In the end, all of the Avengers but Captain America and Hawkeye have joined the Legion of the Unliving but the archer saves the day by playing on the Grandmaster's gambling jones. He gets the Grandmaster to try to pick the one of two arrows that has a modular arrowhead on it. The Grandmaster picks wrong and is so distracted that Death frees herself and overpowers him. Of course, the Grandmaster never had a chance. Hawkeye cheated. Neither arrow had a head. A grateful Death (ahem), returns the Avengers to the living.
OK, that's the story. Here is the point. When Norman Osborn returned to the Spidey books and declared that he had never been dead, a whole slew of continuity-defenders pulled out their Avengers Annuals and said, "oh yes, you were! There you are with the other dead guys, pulling duty for the Grandmaster!" So, is this worth wriggling out of? Or should the Goblin's appearance in this story simply be forgotten?
Marvel seems to have decided to forget about it but, in case they change their minds, here is an extremely easy explanation for the entire problem. Since, the Grandmaster has conjured up these opponents (they suddenly appear in a flash of light), we have only his word that they are the spirits of dead heroes and villains. Or even that they come from the present. The Goblin may simply be a construct, an illusion, another's spirit shaped by the Grandmaster into believing himself to be the Goblin, or even the spirit of the Goblin plucked from sometime in the future. After all, in the Grandmaster, we are dealing with a being of immense power. We are also dealing with a figure, as the end of this story indicates, who (like Hawkeye) cheats. Why should we believe anything that he tells us?
So, stop worrying about this one, all you continuity-lovers. This one is explainable. This one easily works. Now, all that Scrier, Judas Traveler, Osborn Journal stuff... that is another story.