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A Coeurl (AKA a Displacer Beast, Black Destroyer and Phase Tiger) is a type of intelligent alien beast that resembles a large, lean Earth feline, but with six legs and a pair of tentacles coming out of the shoulders. Based on the type of Coeurl, its tentacles ether terminate into tentacled-fingers (Black Destroyer), suction-cups (from The Voyage of the Space Beagle) or barbs. It is also noted that its forelegs are twice as long as its hind legs. Their ears ends in wavering antennae. They appear indifferent to environment and can survive in different atmospheres. They also have the ability to manipulate EM radiation (referred to as "electric vibrations" in the story) at will, and seems to communicate via this method.

They sustains themselves by feeding upon a substance it calls the Id of other beings. This "Id" is mostly found in bones of living creatures, and it is so scarce that they become ruthless hunters to consume enough to sustain themselves with enough Id to survive. They actively avoid their own kind in order to not have to compete over the scarce resource.

This creature is based on the Coeurl from Black Destroyer (1939) and The Voyage of the Space Beagle (1950) by A. E. van Vogt. In Advanced Dungeons & Dragons, they are called "Displacer Beasts" and in Labyrinth Lord, they are called "Phase Tigers". They are also fund in the Final Fantasy video game series, the manga and anime Dirty Pair, the MUD (multi-user dungeon) game Lusternia, and in the MMORPG Guild Wars 2, all using the name "Coeurl."

Conversion Notes

As they are fund in Labyrinth Lord as "Phase Tigers", incorporating them as monsters requires little or no work. Making them playable might require some added effort.

Here are the stats of a Phase Tiger (which can be easily renamed to whatever the Mutant Lord desires):

Phase Tiger

No. Enc.: 1d4 (1d4)
Alignment: Neutral
Movement: 150' (50')
Armor Class: 4
Hit Dice: 6
Attacks: 2 (tentacles)
Damage: 2d4/2d4
Save: L6
Morale: 8
Hoard Class: XIX
XP Value: 820

The phase tiger is not truly a cat, but is fairly intelligent and resembles a six-legged tiger with a long, scaly reptilian spiked whip on each shoulder. The whips have sharp barbs, which inflict 2d4 hit points of damage each. All opponents of a phase tiger receive a penalty of –2 to hit, due to the magical ability of the phase tiger to seem to be in a position that is 3' from where it actually stands. In addition, phase tigers have a saving throw bonus of +2 (all saving throws). Blink dogs are hated enemies of phase tigers, and a phase tiger will seek to kill any blink dogs encountered.

Mutations: None

(Mutant Lords may alter this freely, adding an additional 250 EXP per new mutation or ability as long as HD remains the same)

Making a playable Coeurl akin to the works of A. E. van Vogt requires...

(work in progress)

Pathfinder Coeurl

From the Pathfinder Adventure Path #22: The End of Eternity (Legacy of Fire 4 of 6), the Dispalacer Beast is brought back to its roots as the classic Coeurl, presented as a monster using the Pathfinder rules. Here is a conversion using the Mutant Future rules:


No. Enc.: 1 (1)
Alignment: Chaotic or Neutral
Movement: 120' (40')
Armor Class: 3
Hit Dice: 10
Attacks: 2 or 3 (tentacles or bite and claws)
Damage: 1d6/1d6 or 1d6/1d6/1d8
Save: L6
Morale: 8
Hoard Class: ?

The above Coeurl possess the senses of an earthly predator (low-light and dark-vision, keen sense of smell and hearing, etc.), plus a special sense that would allow them to presive the environment around them, even if blinded, which also grains them a form of telepathy out to 100 ft. Their tentacles, with a reach of 15', are able to hold objects like normal human hands and possess the ability to corrode metal objects they come into contact with, up to a 10-foot-cube of metal per minute! Magic items made of metal that comes in contact with their tentacles must make a save or loose their powers and dissolved into rust. On top of that, their ability to manipulate vibrations can deal an additional +2d6 points of sonic damage to constructs, disrupt incoming range weapons (like arrows and thrown weapons) with a -4 to-hit, or to allows them to pick locks and disrupt mechanical devices with a ??% chance of success out to 15 feet away. This ability requires concentration on the part of the Coeurl and each can be done three times a day. The ability to manipulate vibrations is nullified by magical or technological silence effects. They hake half damage form electricity and are immune to sonic attacks.

Powerfully corded muscles ripple beneath the ebon flesh of this strange, sleek feline. Similar in shape to an oversized panther, the lean beast’s forelegs stretch farther than those to the rear, each ending in powerful claws. Rather than ears, curling tendrils flit at the sides of its head. Most distinctive, though, are the twin tentacles rising from the beast’s shoulders, powerful appendages that slice through the air like living whips and terminate in clusters of thin spines.

Lean and deadly, the animalistic appearance of the alien coeurls belies a keen intelligence and the tempered patience of a masterful hunter. Although similar in form to a wiry jungle cat, coeurls’ forelegs are longer than their rear, giving the shadowy-skinned, hairless creatures a more elevated posture than a common feline. Rather than ears, bundles of wavering antennae extend from either side of their heads, delicate organs capable of detecting sounds and other, more enigmatic sensations. A coeurl’s most distinguishing trait is the pair of powerful black tentacles that extend from its shoulders, each ending in a cluster of flexible, barb-like digits capable of manipulating objects just as nimbly as a human hand.

A typical coeurl stands approximately 3-1/2 feet tall and about 8 feet long, with a densely muscled body weighing around 650 pounds.

Ecology Coeurls are not native to Golarion, but have adapted well. Sages speculate that the deceptive creatures came to this world thousands of years ago via the ancient and mysterious portals that connect the various planets of the solar system. However, while the deadly felines have been encountered on other worlds—notably on Castrovel and Dykon, one of the moons of Bretheda—none of these populations seem significant enough to suggest the creatures’ place of origin. Thus, some suspect that coeurls hail from some place beyond Golarion’s solar system, and have traveled throughout the stars and planes in search of creatures capable of providing them with sustenance. While intelligent, coeurls prove notoriously difficult to communicate with, in part due to the strange method of electrical manipulation that typifies their native language, but largely because most seem disinterested in talking with creatures they view as food.

Although built like deadly feline predators, coeurls require more than mere animal flesh to survive, their strange physiologies being dependant on a poorly understood element they call id. Produced by and contained within living creatures—primarily within bones—this id nourishes coeurls just as food and water do most terrestrial beings, and without it, the tentacled felines starve and die. Seemingly unique throughout creation in their desire for this sustenance, coeurls mercilessly hunt all manner of creatures to sate their need for this unusual element. Harvesting id proves just as fatal and gory as an attack by a jungle cat, but coeurls seem to care little about the lives they extinguish in their feeding. Regardless of how much they consume, coeurls never prove completely sated, the natives of Golarion possessing id energy in amounts likened to drops of moisture collected from fog, hardly enough to sustain thirsty creatures used to drinking from eternal fountains.

Habitat & Society No environment on Golarion seems to perfectly suit coeurls, leaving most irritable and frustrated. Those who deign to communicate with sentient beings complain that the world doesn’t “pulse,” lacking some inherent energy coeurls find favorable. Those rare individuals who hunt on Golarion tend to linger in areas of frequent thunderstorms or in places known for strange electrical properties—such as some of the Darklands’ mysterious vaults or high desert mountains—but endure discomfort in their hunts for id. Due to their extreme rarity, coeurls infrequently encounter one another. Yet, beyond the mere happenstance of meeting others of their race, the alien hunters seem to actively avoid their own kind. While the cunning creatures might simply not wish to compete against their brethren for Golarion’s sparse id resources, it’s also possible that the strange predators don’t wish to be tempted by their kin and the copious id others of their kind likely possess. In either case, coeurls on Golarion rarely approach one another, their isolationist tendencies overriding any racial imperative for companionship or reproduction.

Strangers to Golarion, most coeurls harbor memories— either personal or those passed down through some inherited consciousness—of a racial homeland and a complex society long since lost to their people. Many coeurls actively seek to rediscover their lost home and might interrogate prey about what they know of magical portals or methods of interplanar travel before brutally harvesting their id. In some rare cases these deadly felines form temporary relationships with creatures capable of providing them with the transportation or sustenance they require, particularly powerful wizards, outsiders, or the mysterious denizens of Leng.