An illusion that relies on the sound of the flute. Whoever hears it will be assailed by the vivid sensation that their limbs have been fastened with sturdy ropes, thus becoming unable to move about freely. Even with physical intervention from an outside force, the body is robbed of all mobility, and consciousness itself progressively fades away. At the same time, they are fed morbid hallucinations, which makes it also possible to run them down mentally. Given that the means of transmission is sound-based, it has a large range of effectiveness, on top of which it can be applied even without knowledge of the enemy's position, which makes for an exceedingly convenient technique.
Mateki (魔笛) is the Japanese name for Mozart's famous opera Die Zauberflöte.
When Shikamaru Nara was caught by this illusion, in the manga, the flesh of his arm was melting off his bones; in the anime, his entire arm was melting, including the bones.
In the Ultimate Ninja series, Tayuya uses this technique when she enters the Curse Mark Mode Stage 2. Here she imprisons the enemy and all three ghosts attack the opponent.
After injecting himself with Tayuya's DNA, Kabuto gained access to this ability through a doppelgänger of Tayuya which emerges from the base of his navel-snake. He uses a doppelgänger of Kimimaro to create a flute made of bone in order to use the technique. Kabuto's version of this technique has the victim wrapped with snakes instead of ropes.
In Tayuya's character profile in the Second Databook, this technique is called "Demonic Illusion: Phantom Sound Chains" (魔幻・夢幻音鎖, Magen: Mugen Onsa).
In his anime rematch with Tayuya, Shikamaru demonstrates that one can shield themselves from the genjutsu's effects if they plug their ears before coming within range of the flute's sound.