If you look on page 15 of chapter 429, you will notice that the 6th pain notices something...(
Naruto 429 page 15 | One Manga ).
And then if you turn to page 16-17, you will notice that there is a small explosion (or maybe a summon-like creature) in the middle of the crater...(
Naruto 429 page 16-17 | One Manga ).