Time is a Harsh Mistress
Of all the Spider-Man villain premiers I've read (which, to be fair, isn't a whole lot at this point) I think the Scorpion's is my favorite. Not only does he have an interesting origin story, but he's also the first villain to really lay into Spidey. Scorpion defeats Spider-Man multiple times in this issue and he's set up as a really intimidating foe. It also shows how resilient Peter is. Each time he's defeated, he gets up and charges into battle with the Scorpion again, despite knowing that he's outmatched, because he knows that if he doesn't people are going to be hurt. This issue does a great job of showing us who Peter is through action.
#20 was a great issue, and if it was the only appearance of the Scorpion, he'd be one of my favorite villains. Which leads me to ask the question: What happened? The Scorpion is treated as a second class villain nowadays despite his awesome introduction. Not sure how that happened. Funny how the Scorpion deteriorated as time went on while The Green Goblin went on to be Spider-Man's greatest foe despite his almost laughable introduction. (It involved Goblin convincing a Hollywood director to do a film about Spider-Man so that when Spidey showed up for filming, he could trap and attack him. Really.)
Anyway, there's lots of good stuff here. Awesome villain (at the time), good origin story, and wonderful characterization.
