Amenosubaruboshinomikoto: Ryūgū

The user extends their arm outward at the target with an open palm. A massive purple ball of energy is then unleash, followed by a immense demonic purple serpent. Its power is able to compete with the Parent and Child Rasengan.

Trivia

 * This technique references the tale of Urashima Tarō, Urashiki's namesake. In the story, Urashima rescues a turtle and is rewarded for his kindness with a trip to "Ryūgū-jō", the underwater Dragon Palace, home of the dragon kami of the sea.