Attack of the Twin Demons

The Attack of the Twin Demons technique allows Sakon and Ukon to merge their bodies using their kekkei genkai. Typically, Ukon is dormant in Sakon's body, with his head protruding from the back of Sakon's neck, although he can move freely inside his brother's body and protrude any part of his body from anywhere on his brother's body.

Trivia

 * When Kabuto Yakushi used this technique in chapter 585, he called it Sakon's.