TouchDrain Mercantile is a Destruction spell available in The Elder Scrolls III: Morrowind that temporarily lowers the value of mercantile. The skill returns to its original value when the spell ends.
This spell is not available for purchase in Morrowind or expansion packs. Although not intended for use by the Nerevarine, it can be acquired on the PC by using the console command:
Player -> AddSpell "touchdrain mercantile"