Spiders are first encountered on B6F. They can be found on the early floors of the 2nd stratum, the Primitive Jungle. Their Cocoon skill binds the arms of one party member and with low health they will start using Paralyze, which deals damage to one party member and, obviously, has a chance to paralyze. They are actually quite weak and they are also vulnerable to fire, making them easy prey for parties with Fire-based alchemists.