9. Nemesis (Resident Evil 3: Nemesis)
There's something utterly terrifying about an enemy that is seemingly un-killable. Most monsters, no matter how scary they may be, will go down eventually and never return. The Nemesis, however, will show up throughout Resident Evil 3 and that's horrifying. In fact, he makes eleven appearances throughout the game and he must be temporarily defeated in three of those to progress. You can run away from most of his encounters (which is highly advised) but he has the ability to follow you and suddenly attack you again. This all makes for great atmosphere though; being chased by a menacing terror is pretty cliché in the horror genre but it works. We want to see the titular villain defeated, just so we don't have to live our lives in fear of what might be chasing us; finishing Resident Evil 3 is somewhat of a relief for that reason. Still, keeping the player in constant fear is a great way to create emotional attachment to a game and the original Resident Evil trilogy does it better than most. Nemesis might eventually be killed by Jill Valentine but not before he's scared the life out of her (and us) on several occasions.
