If you guys have read the latest Naruto 570, you would have noticed Tobi’s technique uses Chakra Chains to completely sucks in Son Goku, the Four-Tail Beast. This technique was very similar to one which Pain/Nagato used.
When Naruto took the black stake out of Son Goku’s body, it separated both Roshi, the Jinchuuriki, and Son. Son predicted that he would the ability to freely control himself, but in fact that didn’t work as Tobi still had control over Son.
The main reason Tobi released this unknown and unnamed jutsu was to take back Son, Tobi wanted to keep both Roshi and Son together as he is the Jinchuuriki, and it is much easier for Tobi to control Roshi using the black stake, but as the stake was removed both the body and the beast are now separated.
This technique is similar to one which Pain/Nagato used when Konoha was being destroyed. If you remember this far back you guys need a medal! Nagato had a couple of similar technique which had a similar purpose, which was to pull people into a different type of existence or within a hole. These technique were Nakara Path, Outer Path, Outer Path: Samsara of Heavenly Life and Human Path (Soul Removal).
That was an amazing episode, hopefully all of you manga readers understand why he was sucked in. If there’s anything else you guys don’t understand, drop me a comment below. The next chapter Naruto 571 is probably going to be one amazing chapter as both Kurama and Naruto are now partners! They will work together to bring Tobi down!