Bazlegeuse

Enraged. If Bazlegeuse takes more than over 20 damage from a single creature within one turn, it becomes enraged. It's attacks gain an additional 1d6 fire damage. Additionally, it can make another Slide attack or another Exploding Headbutt as it's multiattack action. His enraged state ends if he takes more than50 damage in one turn, or if he is stunned.

Ramping Scales. As an bonus action, Bazlegeuse can charge his scales with a more powerful explosive energy, adding a charge point onto itself, to a total maximum of 2. Once charged, it's next attack with deal an additional 1d6, or 2d6 of fire damage depending on what level of charge he is in.

Multiattack. Bazlegeuse make 2 Slide attacks (3 if enraged)

Slide. Hits everything in a straight line for 20ft, and travels the full 20ft no matter what. +8 to attack: On hit, 2d6 Bludgeoning. In addition to this, if he has scales charged, the slide leaves a trail of scales drop every 5ft travelled, which then explode during his next turn within a 5ft radius of the scales. Every creature within that radius must make a dexterity saving throw (DC15) or take 1d6 fire damage, A successful saving throw halves the damage.

Explosive Headbutt. Reach 10ft, single target. +8 to attack: On hit, 1d12 Bludgeoning. In addition to this, If he has scales charged, during the headbutts contact with creature, his scales with explode with a 5ft (if his scales have been charged once) or 10ft (If his scales have been charged twice) radius upon impact. they will have to make a constitution saving throw (DC 15) or take 2d6 fire damage, A successful saving throw halves the damage.

Scale Dance. Bazlegeuse discharges his charged up scales and spreads them all around him in a 20ft (If his scales have been charged once) or 40ft (If his scales has been charged twice) radius covering the ground with his charged scales. During his next turn, the scattered scales explode within a 5ft radius of the scales. Every creature within that radius must make a dexterity saving throw (DC16) or take 3d6 fire damage, A successful saving throw halves the damage.

Soaring Strike. Bazlegeuse takes flight leaving him 20ft in the air, and then scatters his scales in two 20ft vertical lines, leaving him airborne and setting up his scales, having one scale per 5ft. The scales scattered then explode during his next turn within a 5ft radius of the scales, and creatures caught in the blast will have to make a constitution saving throw (DC 15) or take 2d6 fire damage. A successful saving throw halves the damage. 

Scale Charge. Bazlegeuse charges its Scales, he can do this a maximum of 2 times.