When an Akimichi enters Butterfly Mode, fat in their body is converted into densely concentrated chakra. As the chakra leaks from their backbone, it becomes visible through friction with the shoulder blade, taking the appearance of butterfly wings. The Akimichi can focus the chakra from the wings into their fist, allowing them to use this technique: a single punch to a target with the Akimichi's full weight placed behind it. The Akimichi's natural strength, combined with the sheer amount of gathered chakra, makes this punch devastating, capable of fracturing the ground. Though quite effective against most targets, if the Three Coloured Pills are used to enter Butterfly Mode, that in turn makes this technique a double-edged sword.
- Tō no Sho, page 248