Spiky Human Boulder Tank - an enhanced version of the Akimichi clan technique "Human Boulder Tank". The user wraps their body in ropes with kunai attached to them, after which they apply the Size Expansion Technique and perform an ordinary ram in the form of a ball. The kunai protrude outward, working as spikes: they strengthen the rotation and make the attack noticeably more destructive. In battle, Choji Akimichi later abandoned the ropes with kunai and began rapidly growing his own hair, wrapping it around his body and making it very hard and sharp. The hair provides many more spikes and requires less preparation time than wrapping with kunai.