Source: thegreengoblinshideout.com

9. Spider-Man: Sins Past

As I mentioned, One More Day is too obvious an entry for this list, but Sins Past needs to be addressed.

Sins Past opens with Peter Parker being attacked by two mysterious assassins, one of whom looks shockingly like Gwen Stacy. He also receives a long lost letter from Gwen, sent before her death. Turns out that, in the months before, Gwen became pregnant with twins and gave birth to them in secret.

But before you start freaking out that these are Peter's kids, don't worry! They aren't! No, no"¦they're Norman Osborn's kids. Much worse. Yeah, turns out that college age Gwen Stacy was having an affair with drawn-like-he's-fifty Norman Osborn. Ewwwwwwwwwwwwwww.

Oh and Mary Jane knew about this the whole time. Yep! This comic was almost instantaneously forgotten and has been wiped wholesale from continuity, but holy hell, is it a bad read. It hurts me to look at it. So gross.