From the ground around the caster, as he raises his arms, a dense fog rises, obstructing vision and muffling sounds. The cloud of mist has a diameter of Power*3 meters and a height of about 3 meters. The higher the Power of the spell, the denser the fog cloud. The cloud is stationary and forms around the caster as the center.
The fog acts as an extension of the caster's senses through the magical connection to him. As long as he remains in the fog himself, he can instinctively perceive all movements within the cloud and better hear all sounds within it (Perception + 2).
Rumor has it that loud, manic laughter while summoning the fog increases its later, threatening effect. However, this can almost certainly be dismissed to the realm of myths and legends.
The fog cloud persists for Power minutes.