Ishi Ishi no Mi

The Ishi Ishi no Mi is a Paramecia-type Devil Fruit that allows the user to absorb, manipulate and merge with stone, making the user a Stone Assimilation Human (岩石同化人間). "Ishi" means "stone" in japanese. It was eaten by Pica.

Strengths and Weaknesses
The Devil Fruit's primary ability is the power to merge and assimilate with stone or earth. This allows the user to take control of anything made of earth that they come in contact with. In Pica's case, he can control Doflamingo's castle as if it were his own body, as it is entirely made of earth.

Aside from the standard Devil Fruit weaknesses, this ability curently has no other known vulnerable point.