Warning: SPOILERS for Spider-Man #3
Marvel's Gwen Stacy's death is repaid: by erasing Spider-Man from all of existence.
Amazing Spider-Man #121 ended with the shocking death of Gwen Stacy at the hands of the Green Goblin, but it wasn't entirely Norman Osborn's fault. Sharp readers noticed a "snap" sound effect next to Gwen's neck when Peter caught her with his webbing, and believed that Spider-Man, in his attempt to save her, actually caused her death. Peter would be consumed with guilt, grief, and a powerful urge to murder the Green Goblin - but characteristically allowed him to live, showcasing his mercy even in the face of profound loss.
In Spider-Man #3, written by Dan Slott with art by Mark Bagley, Spider-Man and his friends from the Spider-Verse are up against a villain that threatens the multiverse, but half of the group are transformed into spider-monster hybrids against their will. Peter is confident that he won't be harmed - as the so-called Chosen One, he is destined to survive and save the Spider-Verse. Unfortunately, Gwen overhears this sentiment and uses an opportunity to stab Spider-Man in the chest with an otherworldly dagger - the same one that removed Spider-Woman, Jessica Drew, from existence in the previous issue. "This - this isn't supposed to happen..." muses Peter, before "unraveling" and being erased from reality.
Gwen Stacy's Revenge Erases Spider-Man From Existence
Gwen's actions are not her own - she is a monstrous version of herself, after all - but there remains the possibility of cross-universe hatred over a certain other character. Mary Jane was married to Spider-Man for over twenty year of real-world time, and Gwen would be terribly upset at many aspects of their relationship - chief among them, the fact that Peter never told Gwen he was actually Spider-Man before her death. Many readers lament Gwen dying when she did; she never the closure she deserved in life, and Spider-Man has felt guilty ever since.
It is highly doubtful that Spider-Man will remain dead; Peter Parker has died before (most notably in Avengers: Infinity War, Spider-Man: Into the Spider-Verse and multiple universe-ending events in the comics) and has always returned after a brief absence. However, the fact that he is killed at all (by Gwen Stacy no less) is quite shocking for fans of the character. Spider-Man's death at the hands of Gwen Stacy is a horrific moment, but no less horrific than Gwen's original death over 50 years ago.
