After Mū splits himself to make an identical clone, one of the halves throw the opponent up in the air, and vanishes from sight. The other half appears in the air, and both halves shoot a Dust Release attack, catching the opponent in the middle of it.
In the manga and anime, Mū is incapable of using his Dust Release while in a split state.
This technique seems to be inspired by chapter 546, where Ōnoki and Mū used Dust Release against each other. Similarities include one user being on the ground while the other one is in the air, and the resulting explosion, which expands and consumes nearby parts of the environment.