Bazelgeuse

Condition Buildup. If the Bazelgeuse would be inflicted with a condition that it is immune to, it gains a stack of Buildup. Once the Bazelgeuse has 2 stacks of buildup, it loses all condition immunities. Then, once it is inflicted with a condition that it had an immunity to, it loses all stacks of Buildup. Once it recovers from that condition, it regains all its condition immunities.

Primed. Once the Bazelgeuse drops to or below 115, 70, and 45 HP, it becomes Primed for 1 round. While the Bazelgeuse is primed, each Melee Weapon Attack it performs deals an additional 3 (1d6) fire damage, and new Bomb Scales explode immediately.

Breakable Tail. Once 45 or more slashing or piercing damage has been dealt to the Bazelgeuse's tail, the tail is severed and Tail Swipe can no longer be used.

Breakable Wings. Once 65 or more slashing or piercing damage has been dealt to the Bazelgeuse's wings, the wings are torn, and the Bazelgeuse can no longer fly.

Stunnable. Once 25 or more Bludgeoning damage has been dealt to the Bazelgeuse's head, attempt to stun the Bazelgeuse for 1 round. This is repeatable.

 Headbutt. Melee Weapon Attack: +8 to hit, reach 5 ft., one target. Hit: 20 (3d10 + 5) bludgeoning damage.

Hip Check. Melee Weapon Attack: +8 to hit, reach 5 ft., one target. Hit: 15 (2d10 + 5) bludgeoning damage. Target must make a DC 14 Constitution saving throw, becoming knocked prone on a failed save.

Tail Swipe. Each unit within a 5 ft cone behind the Bazelgeuse must make a DC 14 Dexterity saving throw, taking 15 (2d10 + 5) bludgeoning damage on a failed save.

Bomb Scales. Once per round, the Bazelgeuse can use a bonus action to drop up to 3 Bomb Scales within a 5 ft radius. These scales will explode immediately if the Bazelgeuse is Primed. Otherwise they explode when hit with an attack. When a bomb scale explodes, each creature within a 5 ft radius must make a DC 14 Dexterity saving throw, taking 9 (3d6) fire damage on a failed save. Up to 6 Bomb Scales can be on the board at a time.

Screech (Recharge 2-3). The Bazelgeuse lets out an ear-piercing screech. Each creature within a 15 ft sphere must make a DC 14 Constitution saving throw, becoming incapacitated for 1 turn and losing concentration on a failed save.

Fire Breath (Recharge 5–6). The Bazelgeuse exhales a blast of fire in a 15-foot cone. Each creature in that area must make a DC 14 Constitution saving throw, taking 42 (12d6) fire damage on a failed save, or half as much damage on a successful one.

Divebomb (Aerial Only). The Bazelgeuse dives from the skies, crashing into the ground hitting anything that does not get out of the way. All creatures in a 30 ft line must make a DC 14  Dexterity saving throw, taking 20 (3d10 + 5) bludgeoning damage on a failed save. Move the Bazelgeuse to the end of the 30 ft line, stopping early if it hits immovable terrain.