Some would say that nebulas from which it stars are born. Sometimes, though, this comic womb produces only stillborn matter and eventually becomes a hungering, hateful force onto itself. Pulling itself together into a congealed mass of dust, rage, and radiation, the nebula seeks out life and burns it to ash. Thankfully, the resulting ooze is much smaller than a heavenly feature, but it is still a deadly menace floating through the spaceways or searing its way through a planetoid’s populace. Even worse, humanoids slain by the nebula find no rest but instead rise as an ever-growing tide of Solarwind Specter just as bent as reducing all to dust.

Congealed Nebula

Huge ooze, unaligned

Armor Class 8

Hit Points 150 (12d12 + 72)

Speed 276 (24d10 + 144)

Climb 20ft

Str 23 Dex 7 Con 22 Int 1 Wis 12 Cha 3

Saving Throws Con+9

Skills Perception +4 Damage Immunities acid, cold, radiant

Condition Immunities blinded, charmed, deafened, exhaustion, frightened, prone

Senses blindsight 1000 ft. (blind beyond this radius), passive Perception 14

Languages -

Challenge 8 (3,900 XP)

Amorphous.

The congealed nebula can move through a space as narrow as 1 inch wide without squeezing.

Birth Horror.

Any time a humanoid is slain by one of the congealed nebula's attacks, a solarwind specter burns its way out of the corpse in 1d4 hours. Corrosive Form. A creature that touches the congealed nebula or hits it with a melee attack while within 5 feet of it takes 4 (1d8) acid damage and 4 (1d8) radiant damage. Any nonmagical weapon made of metal or wood that hits the ooze corrodes. After dealing damage, the weapon takes a permanent and cumulative −1 penalty to damage rolls. If its penalty drops to −5, the weapon is destroyed.

Nonmagical ammunition made of metal or wood that hits the congealed nebula is destroyed after dealing damage.

The ooze can eat through 2-inch-thick, nonmagical wood or metal in 1 round. It can eat through 2-inch-thick, magical wood or metal in 1 minute.

Nebulize.

The congealed nebula, it can use its action to polymorph into a huge cloud of radioactive gas, or back into its true form.

While in gas form, the ooze can’t take any actions or manipulate objects. It is weightless, has a flying speed of 100 feet, can hover, and can enter a hostile creature’s space and stop there. It has advantage on Strength, Dexterity, and Constitution saving throws, and it is immune to all nonmagical damage. It also loses all of its other Abilities.

Any creature that begins its turn or enters the space the gas occupies must succeed on a DC 17 Constitution save or take 13 (3d8) radiant damage.

Spider Climb.

The congealed nebula can climb difficult surfaces, including upside down on ceilings, without needing to make an ability check.

Actions

Multiattack.

The cosmic siren makes four attacks, two with its claws and two with its tail. Alternatively, the cosmic siren can shriek twice.

Claw.

Melee Weapon Attack: +14 to hit, reach 10 ft., one target. Hit: 17 (2d8 + 8) slashing damage.

Tail.

Melee Weapon Attack: +14 to hit, reach 10 ft., one target. Hit: 24 (3d10 + 8) bludgeoning damage.

Shriek.

Ranged Spell Attack: +13 to hit, range 300/900 ft., one target. Hit: 22 (4d10) thunder damage.

Pseudopod.

Melee Weapon Attack: +9 to hit, reach 10 ft., one target. Hit: 19 (3d8 + 6) slashing damage, 10 (3d6) acid damage, and 10 (3d6) radiant damage. In addition, nonmagical armor worn by the target is partly dissolved and takes a permanent and cumulative −1 penalty to the AC it offers. The armor is destroyed if the penalty reduces its AC to 10.