As shadow evocation, but it enables the caster to create
partially real, illusory versions of sorcerer or wizard
evocations of up to 5th level. If recognized as greater shadow
evocation, damaging spells deal only two-fifths (40%) of normal
damage, with a minimum of 2 points per die of damage. For
example, a greater shadow cloudkill has a 40% chance to kill
creatures of 6 HD or less, and creatures of 4 to 6 HD get a
saving throw. Creatures not killed take 1d10 x 0.4 points of
damage each round.
Nondamaging effects, such as a webs ensnarement, are
only 40% likely to work when the greater shadow evocation is
recognized as mostly illusory (roll separately for each effect
and each creature who recognizes the evocation as shadowy).