Submarine Reflection

Submarine Reflection was an offensive attack used by Sailor Neptune. It requires use of her Crystal Treasure: the Mirror.

Sailor Moon S
In Sailor Moon S, Sailor Neptune used Submarine Reflection to reveal Germatoid's true form amongst the many clones.

Black Dream Hole
In the Sailor Moon Super S Movie: Black Dream Hole, Sailor Neptune used Submarine Reflection to reveal Pupulan, Bananu and Oranja's weakness (their pipes). To perform it, Sailor Neptune used her.

Trivia

 * Although this attack is helpful in discovering weakness, Sailor Neptune only uses this attack twice.
 * In the manga version, the kanji that makes up "Submarine Reflection" (深海鏡射) literally translates to "Deep Sea Mirror Morphism".