These are what we call the 'YMMV items.' Things that some people find in this work. We call them 'your mileage might vary' because not everyone sees these things in the same way. This starts discussions in the trope lists, a thing we don't want. Please use the discussion page if you'd like to discuss any of these items.
Demonic Spiders: The Shocktroopers. Not only do they either dual wield MP5 submachine guns or carry a SMAW rocket launcher, but they're also extremely aggressive, are crack shots, and wear heavy body armor that makes them nearly impervious to smaller caliber firearms (unless loaded with armor piercing or other special ammo). Throughout most of the game they show up as Elite Mooks, but during the last chapter you'll be facing them and the Robotanks and gun turrets exclusively in very unforgiving terrain. Hope your squad commanding skills are up to task.