Undead Fog

it expands out from a 360 degree radius of the Sunken Spirit, and reaches out 80 feet, once enveloped in this fog, all creatures besides the Spirit have their vision range reduced to 5 feet, and are vulnerable to all attacks, if a creature is attacked in the fog, they will grow more alert and have their vison increased to 10 feet, additionally, all undead within the fog can see through the fog normally, and gain +5 on all attack rolls.