Contract Seal

When the user implements this fūinjutsu on a summoner, it removes any direct control the summoner has over a summoned creature. Close contact and the summoner's blood appears to be required for the implementation of the seal. Minato Namikaze used this technique to wrest the the Sharingan-controlled Nine-Tails from Tobi's control. Though the Contract Seal removes the summoners ability control its summon, it does not give then user of the fūinjutsu to control the summon in turn, nor does it remove a summoners ability to continue to summon the creature.

Trivia

 * In an anime cutscene of Tobi's storyline in Naruto Shippūden: Ultimate Ninja Storm Generations, Hashirama performs the technique on Madara during their battle though in the manga, the revived Madara attempted to summon Kurama during the Fourth Great Shinobi World War, reinforcing that the summoner doesn't lose the ability to summon a creature, just removing the nature of control over it.