One crafty mage, who saw how the spell summon lesser spores was a reworking of
an early magical failure, did some research of his own. He saw that the
accident which the lesser spores spell was fairly minor, and that the
resulting spell was also a fairly minor spell. He remembered learning about
another  earlier tale, where several practicers of magic were trying to
jointly conjure a great amount of power. The result was a tremendous
explosion, which killed all who were involved. By researching this event, he
was able to recreate the  scope of the energy conjured, and tailor it into a
stable form. The result, is a spell, while similar to the lesser spores, that
is much more powerful.