10 Terrifying Monsters From Non-Horror Video Games
3. The Flood - Halo Series
There's a reason that the Forerunners were scared enough to make a massive collection of space-rings to wipe out all life in the universe. That reason is The Flood.
The Flood are real nightmare-fuel; parasitic alien lifeforms that reanimate dead flesh, twisting the formerly alive into grotesque monstrosities that come after you in absolute hordes, time after time again.
Their introduction in Halo: Combat Evolved is one of the more unnerving parts of the game. Until this point, you'd been dealing only with the Covenant, and now you've got to deal with hulking brutes with far too many tentacles, as well as horrible little things that skitter along the floor towards you.
Even scarier? The Flood are an enemy that can exponentially grow. If they defeat something, they can then infect it and create more of their hideous army, effectively becoming one of the biggest threats the entire galaxy will ever have to face.
They also all act as one entity through Graveminds, which means that if some Flood are after you, you can bet that the rest of them know you're there too.