Ryu Ryu no Mi, Model: Pachycephalosaurus

The Ryu Ryu no Mi, Model: Pachycephalosaurus is an Ancient Zoan-type Devil Fruit that allows the user to transform into a hybrid and full version of a pachycephalosaurus at will. It was eaten by Ulti.

Etymology

 * Ryū (竜) is Japanese for "dragon" and can be found in the Japanese term for "dinosaur" (恐竜).

Strengths and Weaknesses
Much like other fruits in the Ryu Ryu no Mi series, this fruit grants a tremendous increase in the user's physical strength. Ulti was able to grab Monkey D. Luffy and quickly immobilize him, with Luffy being unable to quickly escape despite being tremendously strong himself. The user's skull also greatly increases in size and thickness, which suits Ulti due to her fighting style revolving mainly around headbutting opponents. No weaknesses of the fruit are currently known other than the standard Devil Fruit weaknesses.

Usage
Ulti uses this fruit in combat. Since she is already a strong melee fighter, transforming allows her to enhance the power of her attacks even more. Ulti transforms when she takes her opponent seriously, and her fruit usage is considered by her crewmates to be overkill against most opponents.

Attacks

 * Ul-Meteor (頭銃): While holding her opponent, Ulti rears her head back and prepares to unleash a headbutt in a significantly more powerful version of the Ul Skun technique. She was first shown trying to use this on Luffy, but was unable to execute it due to being attacked by Yamato. Since she was attacked in the middle of saying the attack name, "Ul Meteor" may not be the full name of the attack. This attack is called Ulti-Meteor in the VIZ translation.