Undead Siege

Summons 100d100 skeletons for 24 hours, when one dies it regenerates after 1d20 minutes. Any creature killed by a skeleton conjured by this spell re-animates as a zombie and/or skeleton and serves the caster. All conjured skeletons collapse into piles of bones when the spell ends. Requires Concentration. The skeletons are intended to be an army that can destroy entire kingdoms.