I swear comics need to introduce some sort of cosmic entity responsible for the "Schrodinger's Death" state of characters, whereupon they're dead (i.e. we see their corpse, we see their spirit in Hell, we see them revived as part of the Legion of the Unliving) and they're actually dead... until such time as we discover they were (just resting/in Europe/kidnapped and replace by Skrulls).

"You don't understand! I really was dead until the entity known as Retcon made it so I was on ice in an AIM facility all along. So you really did meet my ghost, because I was dead -then-. But then reality changed and... oh forget it. I'm back."