One Piece"? Does the universe implode upon itself? :-P
Takku Takku no Mi
Level 1--Allows the user to adher any two objects together. ANY. Allows him/her to combine the objects in a way that the new object is fully useable with the functions of the first two.
Level 2--The user can stick together an increasing number of objects, depending on skill level. Can build complex systems, if given the right parts. Or just build "Katamari Damacy" style balls.
Level 3--User can turn opponent into a "tack", and anything (s)he comes in contact with will stick to him or her. May result in opponents being crushed into submission, or even to death.
Level S--Allows user to stick together intangible objects/feelings. Much like Kuma's repelling of fatigue. Can stick together two DF abilities, two wills, etc. Limited to two "objects".