Spider Calling (3.5e Spell)

You summon a number of swarms of spiders (one per level, to a maximum of 18 swarms at 18th level). The swarms must be summoned so that each one is adjacent to at least one other swarm (that is, the swarms must fill one contiguous area). Each swarm attacks any creatures occupying its area. The swarms are stationary after being summoned, and won&rsquo;t pursue creatures that flee.