The Dero Dero no Mi is a non-canon Paramecia-type Devil Fruit that allows the user to dissolve anything into a liquid, including themselves, by shooting beams out of their eyes. It was eaten by Artur Bacca.
"Derodero" (デロデロ,"Derodero"?) is an idiom representing the state where one is hardly conscious and has great trouble keeping on one's feet.
Strengths and Weaknesses
The most common use of this fruit lies in the ability to shoot beams out of one's eyes to dissolve enemy weapons, as demonstrated on Law's sword. The user can also dissolve people's hearts, placing them under the user's control. The victims will die after 24 hours unless the user is knocked out beforehand.
The user is also able to access abilities similar to a Logia by dissolving themselves into liquid. No weaknesses are currently known aside from the standard Devil Fruit weaknesses.
Bacca uses this fruit in combat to bring enemies under his control.
The name of the Devil Fruit ability, 'Dero Dero,' is an idiom that is most commonly used to refer to an intoxicated person and likens a person's state of drunken stupor to the nature of liquids.