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: Assassins. They'll typically dodge your first attack, and throw a completely random counter. It'll either be a jumping attack that takes a second to hit, a kick combo that starts hitting almost immediately (which will hit you because of the previous attack's timing throwing you off), a low attack that also starts to hit almost immediately, and an attack that can only be stopped by a power attack, and is otherwise extremely hard to evade. Oh, and they can do this last move even if you have no power attacks available.