Larval Starspawn CR 17
This gelatinous green monster has a vaguely octopoid head and a face that is a mass of feelers. It has titanic claws, bat-like wings, and a massive, corpulent form.
AC 32, touch 12, flat-footed 29 (+3 Dex, +20 natural, –1 size)
hp 270 (20d8+180); regeneration 15 (fire)
Fort +15, Ref +9, Will +19; +8 vs. divination and mind-affecting effects and effects that attempt to physically move it
Defensive Abilities amorphous, immobility, immortality, overwhelming mind; Immune cold, disease, poison; SR 28
Speed 30 ft., fly 50 ft. (average), swim 30 ft.
Melee 2 claws +26 (1d10+11/19–20), 6 tentacles +24 (1d6+5 plus grab)
Space 10 ft.; Reach 20 ft.
Special Attacks constrict (1d6+5), overwhelming mind, prodigious reach
Spell-Like Abilities (CL 16th; concentration +22)
Str 32, Dex 17, Con 28, Int 23, Wis 25, Cha 22
Base Atk +15; CMB +27 (+31 grapple); CMD 40 (immobile)
Feats Critical Focus, Improved Critical (claws), Improved Initiative, Improved Vital Strike, Multiattack, Power Attack, Staggering Critical, Vital Strike, Weapon Focus (claws), Weapon Focus (tentacles)
Skills Fly +24, Intimidate +29, Knowledge (arcana) +26, Knowledge (geography) +26, Knowledge (history) +26, Knowledge (planes) +26, Perception +30, Spellcraft +29, Swim +42, Use Magic Device +26
Languages Aklo; telepathy 300 ft.
SQ compression, no breath
A larval starspawn can reflexively adjust its mass at will, so that it is effectively impossible to move against its will. A larval starspawn cannot be bull rushed, knocked down, tripped, or otherwise physically moved via a combat maneuver unless it wishes to be, and gains a +8 racial bonus to all saving throws against effects that attempt to move it, including teleportation effects it wishes to resist.
A larval starspawn does not age, nor does it need to eat or breathe. Only violence can bring about the death of one of these creatures.
Overwhelming Mind (Ex)
A larval starspawn’s mind is overwhelming in its power and alien structure. The first time a creature other than an outsider (excluding native outsiders or aberration) makes mental contact with a larval starspawn, it must succeed at a DC 26 Will save or be stunned for 1 round. On a successful save, the creature is merely staggered for 1 round. This effect can occur whether the larval starspawn initiates mental contact (such as by a spell-like ability like dream or sending or up to once per round merely by telepathic communication established with a single creature as a move action) or another creature attempts to do so (such as by detect thoughts or dominate monster). Once a creature is exposed to a specific larval starspawn’s overwhelming mind, it is immune to this effect from all larval starspawn for 24 hours. This is a mind-affecting effect. The save DC is Charisma-based.
Prodigious Reach (Ex)
As a move action, a larval starspawn can redistribute its mass to extend the reach of a single melee attack. When it does so, its reach with that attack becomes 100 feet. This extended reach lasts to the start of its next turn.
Organization solitary, pair, or cult (3–10)
Starspawn are a highly intelligent species from another part of the universe, and many of their abilities derive from the differing fundamental natural laws from whence they come. They can change their proportional size and symmetry at will. For instance, a starspawn could push most of its mass into its wings to give it the needed size to fly, or cause a single tentacle to grow to supreme length—as its body collapses in behind it—to reach a victim at a great distance. As needed, it could also sprout a sensory organ at the end of the tentacle or reach around a target to attack from more than one direction.
In their standard state, they have four limbs and two wings, as well as a face composed of a mass of feelers.
They can alter the proportions of this shape as they please but always adhere to the same basic structure.
Starspawn do not have brains as humans understand them—instead, every part of their body is a sort of nerve or brain cell. Thus, the larger a starspawn, the more intelligent, because its sheer volume increases its intelligence and abilities. Their minds are wholly alien but are full of psionic and magic potential. Great Cthulhu is, technically, just another starspawn, but his enormous size reflects the fact that he is also the most magical and powerful.
Starspawn reproduce by budding or fission: a smaller starspawn simply drops off a large one. The smaller entity retains a good portion of the parent’s wisdom and knowledge, but has fewer or weaker spells and psionics available, as its lesser size means it has a more limited mental capacity.
In any case, even the smallest “larval” starspawn possess a genius-level intellect by human standards, though this is difficult to measure due to the alien nature of their minds. They typically exist on different planes of existence simultaneously and obey different natural laws than those common to humanity.
Starspawn are immortal and almost impossible to kill. When sealed away by magic or physical effects, they can sleep for centuries without difficulty.
Sandy Petersen’s Cthulhu Mythos, © 2017, Petersen Games; Authors: Sandy Petersen, Arthur Petersen, Ian Starcher.