When Gaara plunges himself into sleep, his personality completely disappears, giving way to Shukaku — the One-Tailed beast. An ancient, cruel and capricious creature awakens, one that craves destruction and knows no mercy. His manner of speech becomes rough, arrogant and beast-like. He mocks his opponents, boasts of his power and takes pleasure from battle. In this state, Gaara does not control his actions — he sleeps inside the sand shell, while his body becomes a puppet of the tailed beast. The only way to interrupt the transformation is to wake Gaara by landing a blow that will pass through the sand armor and reach his real body. Shukaku does not like being "kicked out" in this manner, and resists fiercely. In this mode, Gaara feels neither fear nor doubt — only the instincts of the tailed beast and its desire to erase everyone from the face of the earth.