The Nui Nui no Mi is a Paramecia-type Devil Fruit that grants the user the ability to stitch things together and un-stitch them like if nothing had happened. It was eaten by Leo.
This fruit allows the user to stitch objects to any surface. This makes it useful for restraining people, pinning them to the ground, to a wall or even other nearby individuals. The user is also able to undo the stitches of the object with ease, freeing it from their power. The stitches do not harm its victim and do not appear to physically puncture the object