Perhaps the most despised enemy in System Shock 2, the Annelid Arachnid is a pervasive, phobia-inducing spider that you'll come to loathe as you explore the Von Braun and the Rickenbacker. It seems that the Many decided that the Adult spiders weren't annoying enough already, and decided to create some that, while not truly invisible, are significantly harder to see. As such, they like to hide in the dark corners of the Rickenbacker where you encounter them, and leap up at you when you least expect it.
Annelid Arachnids come in three forms: Infant, Adult and Invisible. To see details on the other two kinds, please check their respective pages.
Attributes: High Hit Points, high damage (Toxic), medium attack speed, fast movement speed
Weaknesses: Anti-personnel ammo, incendiary damage
Common Loot: Arachnid Organ
Strategy: In truth, Invisible Arachnids aren't significantly tougher to deal with than the Adult versions, as they have the same number of Hit Points, the same Toxic damage potential, and attack with the same swarming and leaping behaviour. It's easy to justify spending ammo on these guys, especially in the late game when it's plentiful, though it's recommended you save any Worm Clusters you might have for the massive number of Rumblers you'll encounter later on. As always, keep several Anti-Toxin Hypos on hand, or you'll suffer long after your enemies are dead.