Border Guard

This spell creates a border around a warded area. The border discourages interlopers by informing them (via a magic mouth type dweomer) that they are trespassing on warded ground. If the creature so informed doesn't vacate the area within one round, or if any attempt is made to pull energy from the warded land, border guard calls into being a specific evocation spell known to the caster and centers it on the trespasser. The spell to be evoked must be 3rd level or lower. Any damage caused by the spell affects the trespasser only; the ground itself takes no damage regardless of any elemental effects which may accompany the evocation. Thus, the interloper might be targeted by a magic missile, flaming sphere, stinking cloud, web, fireball, or lightning bolt, all without harming the land around him.

The material components for this spell are the materials needed to bring the magic mouth and evocation spells into effect, and four small bone shards to mark the territory to be guarded.