This is the secret technique of the Nubatama Clan, this allows the Leader of the clan to place a special sealing jutsu on each of it's member which stores their maximum chakra resolves after/on the verge of death.
𝐎𝐯𝐞𝐫𝐯𝐢𝐞𝐰[]
This technique was originally created by the 2nd leader of the Nubatama Clan, Kisaki Nubatama, in order to keep their special chakra type from being stolen and experimented with by outsiders. Her other intentions was for this to be used store the Nubatama Clan of the deceased so they may pass it along to the children once they became of age. This technique is only used by the Leader of the Nubatama Clan, and is only known by the members themselves.