Whirlwind of bones

Whirlwind of bones was an arcane necromancy spell invented by Aulstaer Mrelgaunt that animated a pile of bones to attack a target.

Effects
The whirlwind of bones was not actually a wind, just bones that flew around as if they were being held aloft by a whirlwind. The bones flew where the caster directed them, with flawless maneuverability at a rapid pace (almost triple the normal land speed for a human ) out to a minimum range of 680 ft (over 200 m) and operated in a sphere of 20 ft (6.1 m) radius. When the whirlwind of bones came to rest, it inflicted damage on all creatures within its volume. Half the damage was from the bludgeoning done by the bones themselves, and the other half of the damage was from negative energy. Victims could cut the overall damage in half by successfully dodging some of the flying bones.

Components
In addition to verbal and somatic components, this spell required a group of bones roughly equivalent to the skeleton of a medium- or large-sized creature. The bones could not be restricted from taking flight, such as buried underground, or being a part of a living, undead, or constructed creature.