Tameable Phoenix Boss!

A Phoenix boss that could spawn in rare structures in the nether and use firey attacks like fireballs. When killed, it drops Phoenix feathers and Phoenix ash. The Phoenix feathers would be used as an armor upgrade to make you immune to fire when you're wearing it. The Phoenix ash is how you tame the Phoenix, you throw it into fire and a baby phoenix spawns from the ashes. You tame the baby Phoenix with Magma cream, and it defends you with its fireballs against mobs or other players, and it can sit on your shoulder like a parrot. When its fully grown, it can no longer sit on your shoulder but will still defend you. There could possibly be a Phoenix Saddle that you can put on your full grown phoenix to ride it. It wouldn't be faster than an elytra, keeping it wanted and used, but you would be able to control its fire balls while riding it. If your pet phoenix dies, it leaves ashes. If you throw the ashes into fire, your pet is reborn as a baby Phoenix, but you don't need to tame it again. This could add a cool new nether boss, a rare new structure(possibly with valuable/rare loot), and a rideable pet that can't die.