Benihisago

The Benihisago is a giant gourd that was said to be used by the Sage of the Six Paths himself, and is one of the five ultimate ninja treasures. As with the other four treasures, it's usage consumes a large amount of chakra, so much so that a normal human will die in no time.

The gourd, along with three other treasures, were gathered by Kumogakure, and eventually fell into the hands of the Gold and Silver Brothers, who possessed a portion of the Nine-Tailed Demon Fox's chakra, and as such were able to wield the treasures without repercussions.

This gourd "records" a persons soul and seals it away. It is normally activated after the target says the word they say the most, which is recorded on the Shichiseiken. If the victims say the word after their souls have been captured, then they will be sucked into the gourd and be sealed away in it for good.