You can have your own tamed dragon by using the commands, but for a short amount of time. This is a very cool glitch. You can ride and control the dragon but when you ask it to attack a creature it will not and just stay still. It stayed around for maybe 10 minutes then disappeared leaving no trace of it behind.
This dino lacks any real utility due to the fact that it is a boss and therefore cannot be tamed.... But it drops the highest amount of element out of the four bosses if that can be seen as a utility of sorts
Bring Therizinos instead of Rex’s, since herbivores take reduced damage from the fire, and can eat sweet vegetable cakes to regen health quickly. Take about 17-18 theriz, 2 hell pigs, and 1 yuty as well as an OP rocket launcher or shotgun, or substitute 4 theriz for allo’s to get the bleed attack.