Billy

Billy (ビリー) is a giant electricity producing bird from the tenth One Piece movie. He was originally a creation of Dr. Indigo, but he aids Luffy in fighting against Shiki in the air.

Appearance
Billy is giant yellow bird that looks like a cross between a duck and a peacock. He has the head and beak of a duck, but the rest of his body is that of a peacock, the latter is made even more apparent when he opens his fan-like tail. Billy has giant wings, unlike the creatures that he resembles, and can use them to fly. He is usually seen with a runny nose. Due to the special chemical that was developed by Indigo and given to him, Billy is actually much bigger than he is supposed to be normally.

Personality
Unlike the other mutated animals on Merveille, Billy is quite friendly and mild-mannered; although, he is short tempered, as shown when Luffy pulled on his cheek. He is also prone to panic as shown when he thought Nami had drowned. Despite this; however, he can be loyal and courageous.

Relationships
Because Billy produces electricity from his feathers, not many people get close to him out of fear that he might zap them. The only ones to not completely fear him are Nami and Luffy, the latter of which gave him the name Billy. Luffy derived this name from Biri Biri which is the sound effect for electricity in Japanese.

Abilities and Powers
Billy is a special type of bird created by SIQ that produces electricity from his feathers. Despite being rather small compared to other mutated animals, he is able to generate enough electricity to take out large groups of animals quite easily. He is also capable of flying at high speeds and altitudes while carrying a person.

History
Billy was first seen when Indigo him to Shiki, demonstrating his new creation. After shocking Shiki, he is tossed aside. It was then revealed by Indigo that Billy was inhanced using SIQ the inhanced version of IQ. Before Shiki and his men could further harm Billy, he is protected by Nami, and Shiki leaves Billy with her as he and his men leave.

Later, Billy helps Nami escape their captivity, finding the Thousand Sunny. Moments later, Luffy arrives being chased by giant scorpians, and Billy defeats them using his electricity. While Luffy and Nami are discussing what has happened, Luffy officially names Billy. Billy is then used to fly, carrying Luffy and Nami to search for the others.

While flying, Billy begins to have trouble, later revealed to be the affect of Daft Green. Billy, with paper stuffed in his nose, lands with Luffy and Nami in the village Zoro, Usopp, Sanji, and Chopper are resting at.

Later while the Straw Hat Pirates are fighting the Golden Lion Pirates, Billy finds Nami and helps her ignite the explosives to destroy the Daft Greens surrounding Shiki's palace allowing outside animals to add to the chaos. Shiki then arrives to stop Nami, Usopp, Chopper, and Billy from retrieving the IQ medicine to save Nami, but Luffy appears and starts fighting Shiki with the help of Billy. After Luffy defeats Shiki, Billy recovers Luffy who is in his default form after using Gear Third.

After the battle is over Billy is seen greeting the animals and villagers while flying past. He then lands on a rock greeting Xiao.

Trivia

 * His species is known as a Thunder Bird (雷鳥). Coincidentally, "Raichou" also translates to "Rock Ptarmigan".
 * Billy is one of the few animals which Luffy gave name. (Surume being the other)