Pray that the Dice Gods have mercy... because the Demonic Spiders most certainly will not. * Spider Swarms in D&D 3.5 are TERRIFYING for low-end characters: They automatically hit any enemies they're touching for non-trivial damage, are resistant or immune to most normal weapon damage, stack poison on top of that THEN there's a chance that a character can't actually run away because he's COVERED WITH SPIDERS THAT ARE BITING HIM TO DEATH. * Warlocks get the option call such swarms AT WILL, right at the first level if they want. * Your only option, really, is to Kill It with Fire. * Spider swarms? Pshaw. Try leech swarms. * In Dungeons and Dragons fourth edition, Needlefang Drake swarms are Demonic Spiders to low-level characters. They have the ability to knock down charact