Skull Cough (3.5e Spell)

By flooding the target with a surge of necromantic energy, you cause it to overreact against the sickening waves to the point of fatality. On a failed Fortitude save the subject coughs violently for 1 round, unable to do any actions and is effectively helpless until 1 round later, they inexplicably cough up their own skull, leaving their heads to cave in without structural support and perish moments later. A creature which succeeds on the first save must still make a second saving throw, or be nauseated for the duration of the spell. A creature which succeeds on both saves is uneffected.

For creatures which can survive the loss of their head (such as by vorpal), they can survive the loss of their skull as well, taking whatever penalties appropriate for head loss (such as blindless or inability to speak without their jaw).

Material Component: A shrunken skull of a tiny humanoid creature, which is tossed and shatters.