This one came to me in a dream last night.
Range: 30' cone, 20' wide at far end
While chanting the words of this spell the caster digs their fingers into their own belly, ripping open a wound from which erupt thousands of thin, purple tentacles. Anyone caught in the area of effect must save versus death. Failure to save indicates that all bodily fluids have been drained from them, which should prove lethal for many lifeforms. The wound closes the following round, after the tentacles return into the caster's gut.
If the caster succeeds in draining at least one creature of halfling size or larger they will be visibly bloated for 1d6 turns after casting, during which time they shuffle about at half speed. If struck by any piercing or edged weapons while bloated, they will spew blood and other fluids like a cheap horror movie. Casting this spell a second time while still bloated causes the magic-user to explode messily.