Stellar Rorqual

Mouth Compartment. The stellar rorqual's mouth is a compartment that is 60 feet long, 40 feet wide, and 30 feet high with a single entry and exit. The rorqual can control the ambient pressure, temperature, gravity, moisture, and breathable air levels inside its mouth, allowing creatures and objects within it to exist comfortably in spite of conditions outside the rorqual. Creatures and objects within the rorqual have total cover against attacks and other effects outside the rorqual. As an action, a creature inside the rorqual can interact with the crystalline growths inside the rorqual's mouth and sense what the rorqual senses, gaining the benefits of its blindsight.

Stellar Burst. When the stellar rorqual dies, it releases all of its stored solar energy in a massive explosion. Each creature within 120 feet of the rorqual must make a DC 18 Dexterity saving throw, taking 21 (6d6) fire damage and 21 (6d6) radiant damage on a failed save, or half as much damage on a successful one.

Void Flier. When flying between stars, the stellar rorqual magically glides on solar winds, making the immense journey through the Void in an impossibly short time.

Multiattack. The stellar rorqual makes two attacks: one with its head smash and one with its tail slap. Alternatively, it can use Energy Burst twice.

Head Smash. Melee Weapon Attack: +12 to hit, reach 10 ft., one target. Hit: 30 (4d10 + 8) bludgeoning damage.

Tail Slap. Melee Weapon Attack: +12 to hit, reach 15 ft., one target. Hit: 26 (4d8 + 8) bludgeoning damage.

Energy Burst. Ranged Spell Attack: +8 to hit, range 120 ft., one target. Hit: 24 (7d6) force damage.

Planar Dive. The stellar rorqual can transport itself and any willing creature inside its mouth to the Astral, Ethereal, or Material Planes or to the Void. This works like the plane shift spell, except the stellar rorqual can transport any number of willing creatures as long as they are inside its mouth. The stellar rorqual can't use this action to banish an unwilling creature.