Horn Eaters (ツノクイ, Tsuno Kui) are a type of creature featured prominently in the third One Piece movie. They are large herbivorous armadillo-like rhinos that will aggressively attack any horned creature within sight, even if said creature happens to have fake horns, as seen with Luffy (Usopp had him garbed in a ridiculous costume with antlers included). They are used by Butler to herd the various other horned animals on Crown Island in order to chop their horns off.
Square Rhinos (四角いサイ Shikakui Sai?) are animals with a rectangular form and loosely resemble rhinos that live on the Crown Island. When they lie on the ground, it is very easy to mistake them for rocks.
A Hippo Rhino (カバサイ Kabasai?) is a purple rhino with a hippo's mouth. It can be mistaken for a rock when its head is downwards. It's also a good swimmer as it was able to swim far out to the sea. It fell in love with the Going Merry after it landed on it which made it spit out a fish it was choking on. It decided to swim to the Going Merry and propose to it.
The Island Turtle (シマガメ Shimagame?), also known as Mecha Island, is a giant turtle that wakes every thousand years to lay its eggs. These eggs are considered extremely valuable due to being made of gold.
The powers and abilities of a dragon are so strong that not only can it destroy a single town (under the control of D.R. and Cyrano with the use of a Dragon Horn) and bring terror to the public, but killing one made the samurai Ryuma a legend, and stories about him are still passed down after generations.
Dragons were first mentioned by Hogback in the One Piece storyline during the Thriller Bark Arc, where he revealed to Zoro the story of Ryuma and his legendary slaying of a dragon long ago which the latter took in with much scepticism.
Dr. Vegapunk was revealed to have created his own artificial dragons to guard Punk Hazard. The Straw Hats encountered two, both of which were incredibly strong, and one possessing great speed as well. However, both were eventually killed by Kin'emon and the Straw Hats.