Why did headbutting Gaara make Shukaku disintegrate? When Naruto is fighting Gaara in the invasion of Konoha, Gaara takes on the Perfect Possession form of Shukaku. When Naruto punches Gaara in the face, it wakes him up, breaking the Possum Jutsu and making Shukaku no longer be released. When Naruto headbutts Gaara, however, Shukaku disintegrates. What causes this difference in effect?
I think Gaara just lose control over the chakra flow when Naruto headbutted him. With that, he couldn't keep the jutsu which showed the body of Shukaku.