Giant Clam

Setting aside its huge dimensions, the summon looks much like any everyday clam. Bold dark bands run around the rims of both halves of its shell, and the crest of Kirigakure is carved into the upper valve. That village mark places it among the summons openly tied to a single hidden village.

Once its shell yawns open, the clam exhales a mist through its siphons that hangs over the battlefield for as long as the technique runs. Paired with the Second Mizukage's Demonic Illusion: Steaming Multistoried Building, that vapor spawns a mirage so complete that onlookers cannot fix the true location of either the beast or its summoner. The shell itself is remarkably tough, shrugging off Onoki's opening strike, and the animal is unusually long-lived, having served Gengetsu in life and endured all the way to the Fourth Shinobi World War. In keeping with that role, it shows no will of its own and obeys its summoner without question, even when set against Kirigakure's own ninja.

During the Fourth Shinobi World War, Kabuto Yakushi revived the Second Mizukage through Impure World Reincarnation to fight for Akatsuki, and the clam was summoned to meet the Fourth Division on the field. Its open shell blanketed the zone in the mirage, so every strike the ninja threw missed its mark, and even the Mizukage's hint to hit the clam right behind him could not break the confusion. The tide turned once Gaara and Onoki arrived: Gaara's Concealed Sand Picture Cat traced the real clam, and after Onoki's Dust Release and Fist Rock Technique failed to bite, his Ultra-Added-Weight Rock Technique finally shattered it, dissolving the illusion. The name carries mythic weight too, tracing back to the shin of Chinese legend, a shapeshifting mollusk said to breathe out phantom cities and mirages over the sea.