Note: This article contains heavy spoilers! Read with caution!
66, aka Phoenix 66 or Unit 0066 is the final boss of Phoenotopia.
Phoenix 66 is a humanoid with a brown skin and purple hair. He wears a white jumpsuit with no sleeves and short leggings, and his shirt features a symbol that resembles the letter T. He also has a dark blue collar around his neck, which is most likely the device that allows him to be controlled by special keys like the one owned by Billy.
Phoenix 66 was one of the many phoenix weapons that were used during the Great War against the invaders. Like all the other phoenix weapons, he was originally a human being who was experimented on by human scientists and had his DNA spliced with that of the alien known as Adam, which turned him into a super soldier. After a centuries-long slumber, he was awakened by Billy, who had ambitions to annihilate the Galactic Federation and become the King of Earth.
Events of Phoenotopia
After destroying the Computer Guardian, Gale managed to access the heart of the Phoenix Lab where many Phoenix weapons were stored. Billy and his Stellanite soldiers then teleported to Gale's location, where Billy revealed his intentions of, with an army of Phoenixes under his command, annihilating the Galactic Federation and practically taking over the whole universe. When Gale objected to this, he hadher shot by one of his soldiers. Seeing that she survived, he ordered 66 to kill her. 66 summoned a giant beam of ki and struck Gale with it, which seemingly killed her along with destroying the wall behind her. Gale, however, survived this and struck back at 66, slamming him to the wall and temporarily knocking him out cold. As Gale was about to finish him off, she tried and failed to summon the ki. Billy, seeing this, ordered 66 to kill Gale once more. Realizing she wouldn't be able to deal with 66, Gale tried to escape him by shutting the gates she passed, which 66 destroyed one by one. The chase ended in a dead end, where before 66 could finish Gale off, a Collector ship appeared and abducted them both. As 66 was still conscious, some Collectors hit him with a suspension beam in order for him to stop fighting.