Stalking is a very real fear, not only because the very idea of being watched is creepy, but also because of concerns regarding the lengths the stalker will go to. Most horror gamers will be familiar with the "stalker" enemy - antagonists that relentlessly hunt the player down throughout the course of the game. Some popular examples include the Xenomorph from Alien: Isolation, Mr. X from Resident Evil 2, and Slenderman.