The Tsuya Tsuya no Mi is a Logia-class Devil Fruit that grants the user the ability to transform into and manipulate oil. It was eaten by Calypso Sally. "Tsuyatsuya" is Japanese for "slick and glossy."
Strengths and Weaknesses
The most obvious strength of this Devil Fruit is that oil can float on water. While the user becomes immobilized if they touch the ocean, they will float on the surface until they are fished out, wash ashore or starve to death. Even if you ignore this, the fruit is still very powerful. While unable to "grasp" things using the oil, the user can deliver punishing blows while transforming to avoid attacks like most Logia users. In addition, the user can ignite themselves with an external source, adding heat to their attacks; the current user, Calypso Sally, wears flints on the back of her boots so she can make a spark by kicking her heels together for this reason. Users can even change the type of oil they're made of, meaning someone with enough skill and practice can turn parts of their body into high-grade explosives like rocket fuel to dramatically increase their speed and even fly. The primary weakness of this fruit are drying agents, especially the Suna Suna no Mi. When dried, the oil becomes a tar-like substance, significantly slowing the user. Furthermore, since the user can never really experience drowning like a normal Devil Fruit user, touching Seastone or being hit with Haki becomes a jarringly terrifying experience that often leaves them dazed for several seconds.