Drops off Gnawtooth Gary in Abyssea - Vunkerl. The surrounding rabbits drop the pop item and, oddly and fortunately enough, do not link with each other nor NM.
bigups siggy for having a top notch (relaxing, full yigit, +) hmp set. ratedown wiki for lying about 'conserve mp' the piece needs to be equipped when the spell goes off or it will not process.