The flood from Halo because worse still that's actually plausible since the flood is essentially an outer space organism that can infect people just by breathing the air in and they take control of your brain and warp you inside out which is creepy as fuck.
The concept of the Flood is right proper Lovecraftian horror. It was never really depicted in the Halo series as scary as the Flood actually was; we had a brief glimpse of how horrific something like that might be with the short film Into The Aquila Rift, but it's a shame we don't have more media that properly explores the absolute horror of being a living shell for an outer-dimensional species (though, I suppose the movie The Puppet Masters from 1994 comes sort of close) .
The concept of the Flood is right proper Lovecraftian horror. It was never really depicted in the Halo series as scary as the Flood actually was; we had a brief glimpse of how horrific something like that might be with the short film Into The Aquila Rift, but it's a shame we don't have more media that properly explores the absolute horror of being a living shell for an outer-dimensional species (though, I suppose the movie The Puppet Masters from 1994 comes sort of close) .