Suwa Suwa no Mi

Devil Fruit Name: Suwa Suwa no Mi (Swap Swap Fruit)

Abilities: The user is capable of swapping the properties between two objects that he currently comes in contact with. For example, swapping a cannon ball and a piece of marble, creating a dud cannonball and a small marble that explodes in the same manner than said cannonball would upon contact, or swapping the properties between a piece of paper and a sword, creating a sword that is flimsy and doesn't cut, and a paper that will likely cause the most painful of paper-cuts, being as sharp and durable as that sword was prior to the swapping.

Weaknesses/Limitations: User can't switch the properties of a living thing with the properties of an inanimate object. User cannot swap Devil Fruit abilities between users. In addition, the user can only change two things at a time; once he touches something else, the previous changes is nullified; this is a mandatory effect, thus implying that the user would be in need of gloves (for example) if he wishes to maintain a specific swap active.

Edited out some parts that were not allowed or shouldn't be allowed due to potential loopholes or issues generated, I hope that is fine with you. Thus, with these changes done, and the concept of the fruit being left as you intended it to be, fruit's APPROVED.