Polyphonic Plasm

Large ooze, unaligned

Armor Class 11
Hit Points 84 (8d10+40)
Speed 15 ft., climb 15 ft.

16 (+3) 12 (+1) 20 (+5) 1 (-5) 10 (+0) 3 (-4)

Damage Immunities thunder
Condition Immunities blinded, charmed, deafened, exhaustion, frightened, prone
Senses blindsight 120 ft. (blind beyond this radius), passive Perception 10
Challenge 3 (700 XP)


  • Amorphous. The gel can move through a space as narrow as 1 inch wide without squeezing.
  • Amplify Frequency. Whenever a polyphonic gel would take thunder damage, it absorbs that energy instead. The stored vibrations amplify the creature’s sonic waves, increasing damage dealt by the ooze’s next pseudopod attack before the end of its next turn by 7 (2d6).


  • Pseudopod. Melee Weapon Attack: +5 to hit, reach 5 ft., one target. Hit: 10 (2d6 + 3) bludgeoning damage plus 3 (1d6) thunder damage.


A polyphonic gel resembles smoked glass that pulses with multicolored lights in time to an unpredictable rhythm.

This ooze is actually an organic, semi-fluid mass of millions of flexible fibers that constantly vibrate to produce audible frequencies, ranging from hauntingly beautiful to shrill and discordant. These captivating displays often lure observers who mistake their performances and languidly extended pseudopods for friendly gestures. Such observers soon discover that the gels’ bodies course with sonic vibrations that can devastate flesh, bone, and steel as well as break prey into edible chunks.

Although polyphonic gels seem to draw some nutrition out of physical material, they primarily feed on sound.

When feeding, a gel sends out countless pulses that resonate off their prey’s body, the echoes fueling their metabolism.

Each absorbed sound also helps the gel form new fibers, like a brain forging fresh neurons while learning, as the sounds create each fiber and shape its texture. In this way, polyphonic gels gradually grow—physically and in their sound vocabulary—when exposed to new sounds.

Sound Feeder. Polyphonic gels can survive indefinitely if exposed to periodic sound, like a noisy fan or the rush of a waterfall. However, they grow only when supplied a range of sounds and materials to absorb. In practice, the mindless oozes manifest cravings for different sounds that drive them to search for novel prey or specific material types. Polyphonic gels sometimes slither frantically past other food sources in search of a specific type of crystal or pitch of dwarven scream. Previously docile specimens kept in captivity for study often develop these cravings, too.

Despite their keepers’ best attempts to provide a balanced diet, the oozes’ desires can lead to catastrophic breakouts when they disintegrate their holding cells. When fed a varied diet, polyphonic gels can grow with extraordinary speed, doubling in size in a matter of days. Conversely, those oozes deprived of sound altogether (including any trapped in the vacuum of space) starve and gradually wither.

Polyphonic gels can serve as a repository of sounds. In practice, they might repeat their prey’s garbled last words, crooning nonsense phrases with the haunting voices of the departed. Theoretically, though, it should be possible to elicit specific sounds from these oozes by isolating the key fibers, agitating them, and recording the output.

Engineering tests have managed only small successes to date, however, and most consider anything more as impractical.

Early in life, a polyphonic gel spans about 2–3 feet in diameter and weighs a mere 20 pounds. It grows in proportion to its sound absorption and reaches polyphonic plasm status when it spans almost 10 feet across and weighs 400 pounds. Beyond this size, the oozes rarely dedicate nutrients to additional growth, instead focusing on reproduction by budding a new gel that carries away a fraction of its parent’s sonic repertoire. Even when independent, gels tend to shadow their parent plasms until lured away by tempting new stimuli. Gels of all sizes periodically seek each other out, forming concerts of a dozen or more gels that sing to each other for days on end.

The purpose of these gatherings remains unknown. They rarely result in growth, and since the oozes lack any true nervous tissue (much less minds), it seems unclear if these gatherings hold social value for the creatures, though they appear visibly calmed afterward. However, the gels often turn on anyone who interrupts their songs.

Section 15: Copyright Notice

The Dragon’s Hoard #27 © 2023, Legendary Games; Authors Jason Nelson, Michael Mifsud, Robert J. Grady, Darrin Drader, James-Levi Cooke.

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