Bonnon

Twin ponytails as long as her whole body frame her, one dyed blonde and the other purple. Blue shadow rings her red eyes, and a pair of dots sits on her brow. She wears flowing orange sleeves joined to a red bra top, with a skirt made of panels that alternate red and orange. Curled pink earrings and pointed red heels finish the look, though the manga swaps those heels for ordinary pumps.

For a hundred years the spirit has watched over an elementary school run out of a temple. Her attempts to seem threatening fall flat, since Ami tunes her out entirely and mistakes her for an academic rival named Mercurius. Through much of their clash she comes across as bewildered and rattled.

In the manga, Bonnon is the spirit at the heart of the second Exam Battle short. Sensing how hard Ami burns to outscore Mercurius, she assumes the girl must be lovestruck and marks her as prey. After Ami collapses on the way to class and comes to in the nurse's room, the spirit strikes with a love-letter attack meant to steer her by emotion, and Ami feels her stored knowledge draining away. The introduction goes unheard, and certain she is battling Mercurius, Ami becomes Sailor Mercury and wipes the spirit out with Mercury Aqua Mirage before fainting once more.

The anime special runs a parallel course. Ami, sleepless from cramming for high-school entrance exams against the phantom Mercurius, dozes off at prep school under Bonnon's gaze. The spirit trails her home to drain her passion and begins hollowing out her memory. Usagi, Chibiusa, and Mamoru turn up but can do little before Ami transforms and destroys her, still convinced the foe is Mercurius. Her love letters are her chief weapon, clinging to a victim's face and pulling out their knowledge.