When casting Black Hole the affected area becomes enshrouded in darkness and forms a spiraling vortex.  Any creature in the area of the vortex must make a DEX saving throw or be sucked into the vortex causing 10D8 Gravity damage.  Creatures sucked into the vortex are teleported to a random location in the current dungeon or area.  Creatures that make the Dex saving throw take half damage and are knocked prone.

Spell Level Increase

When casting Black Hole as a 4th level spell or higher all creatures in the affected area cannot make a DEX saving throw and are teleported to a random area in the same location and it deals 1D8 more damage per level.  Add 5 feet to the size of the vortex per level beyond 3rd.