Hell of 1,000,000 Needles

The landscape fills with monumental filaments of metal. The needles lance into a cube 30 feet on a side within 500 feet. Each creature in the area takes 13d6 piercing damage, with a DC resolve reflex save against your class DC. Squares in the area are hazardous terrain. A creature takes 6 piercing damage for every square of the area it moves through.

Level (20th) The initial damage is 17d6, and the hazardous terrain damage is 7.