This is a spell cast on the world map. The spell will create an army in enemy territory (must have war status to cast). This army will start attacking the chosen faction and continue until it (the summoned army) is dead (or in extreme cases until the enemy faction is no more). Size of the army is based on the casters intelligence. This would be an expensive spell, but its not a spell to end the game. The point of the spell is to force the enemy to divert attention to a new threat and thereby gaining an advantage over your enemy in war.