On the surface, this may not seem like the most heinous thing a supervillain has done to a hero, but when you look at the human element of it, this is just about one of the most horrible ways to try and bump someone off.
Before Venom made his first full appearance in The Amazing Spider-Man #300, numerous partial appearances and teasers were featured on the pages of the preceding issues. One of these instances involved the very first time Venom actively tried to kill Peter Parker, taking advantage of the fact that he can block his spider-sense by pushing him onto the tracks of an oncoming subway train.
Sure, Peter managed to leap out of the way in the nick of time, but it's chilling how simple this attempted murder was. No elaborate scheme, no monologue, no preamble, just pushing your nemesis in front of a New York train, hoping it will crush him to death.