Sonic creatures are invisible and incorporeal beings that can be found on any plane. They take the form of normal creatures, but they are made entirely of sound, and many scholars believe that these beings were somehow influenced by the Plane of Sound.
Though it is invisible and intangible, a sonic creature constantly makes a terrible noise. This sound could range from a deep hum to a high-pitched keening to a cacophonous racket like that of armor thrown down the stairs. Sometimes the noise a sonic creature makes is somehow related to its corporeal life. A particularly cruel sonic creature’s sound might make a babble of every mean and spiteful thing it ever said, and a birdlike sonic creature might sound like a riotous flock of thousands of birds. All such sounds are obviously unnatural, and most are quite disturbing.
Sonic creatures feed on sounds similar to those they made as corporeal creatures. Thus, a sonic yeth hound might be drawn to follow its old pack, but it might also linger near a wolf or worg pack, feeding off the noises those creatures make. Alternatively, a sonic creature particularly keen on music might seek out bards to feed upon. Sonic creatures must feed on sounds like those they once made for a full day at least once per week or begin to starve. A starving sonic creature often terrifies and wounds creatures in order to force them to make the sounds it needs, or to feast off their screams. Corporeal creatures find pursuit by a sonic creature eerie at best. Some think their pursuer a ghost; others are simply terrified of the noise it makes.
Like most living beings, sonic creatures must regularly sleep. As incorporeal creatures, they have little to fear from foes while they sleep, but most still choose to sleep high in the air or deep within the earth, lest they be disturbed by curious or frightful creatures. Such practices make following a food source for long periods difficult and often force sonic creatures to cast about for new creatures to feed on.
“Sonic” is an acquired or inherited template that can be applied to any living corporeal creature (referred to hereafter as the base creature). A sonic creature uses all the base creature’s statistics and special abilities except as noted here.
Challenge Rating: Same as the base creature +3.
Senses: A sonic creature gains the following:
A sonic creature can see using sound, even while within a solid object. This ability allows it to discern objects and creatures within 60 feet regardless of terrain or barriers that would normally impede vision. Unlike normal blindsight, a sonic creature does not need line of effect to a creature or object to discern that creature or object. A silence spell negates this ability and forces the sonic creature to rely on the base creature’s vision. This ability replaces blindsight. If the base creature has blindsight, the range for improved blindsight increases by the range of the base creature’s blindsight ability.
Armor Class: The base creature’s armor, shield, and natural armor bonuses no longer apply, but a sonic creature gains a deflection bonus to Armor Class equal to its Charisma bonus or +1, whichever is higher. Sonic creatures cannot use or carry equipment of any kind.
Hit Dice: Change all of the base creature’s racial HD to d10s.
Weaknesses: A sonic creature gains the following.
Though an incorporeal creature normally has a 50% chance of remaining unaffected by a spell originating from a corporeal source, silence spells are an exception to this rule for sonic creatures. A sonic creature is considered entangled while within the area of a silence spell. A silence spell also negates all the sonic creature’s normal and special attacks within its area. A silence spell cast directly on a sonic creature does not have a silencing effect on the area or an entangling effect on the sonic creature; instead, it causes the sonic creature to become nauseated for 1 round per caster level on a failed save.
Speed: A sonic creature loses all the base creature’s speeds and gains a fly speed equal to double the base creature’s highest speed, with perfect maneuverability.
Attacks: All of the base creature’s attacks become incorporeal touch attacks. The sonic creature gains a primary incorporeal touch attack if it has no other natural attacks. Each of a sonic creature’s incorporeal touch attacks that was converted from an attack that dealt hit point damage now deals sonic damage instead. If the attack additionally dealt damage of an energy type (such as acid, cold, electricity, or fire), that damage is also converted to sonic damage. If the sonic creature gains an incorporeal touch attack from the application of this template, its damage is based on size as a slam attack as if the creature was one size category larger.
Special Attacks: The sonic creature loses all special attacks that require corporeal contact except those that deal hit point damage. Such attacks now deal sonic damage in the same amounts. The sonic creature also gains the following.
The sonic creature may cause sonic damage to creatures and objects simply by passing through them. As a full-round action, the sonic creature can move up to twice its speed in a straight line. Any creature it moves through can attempt either a Reflex save for half damage or an attack of opportunity. An unattended, non-magical object receives no save. No creature or object can be damaged twice in a round by this attack. Sonic creatures do not damage creatures or objects they move through when not using this ability; the creature has to actually intend to cause damage. The damage dealt by this attack is based on size and is equal to that of a slam attack as if the creature was two size categories higher +1-1/2 times the sonic creature’s Dexterity modifier. If the base creature has a trample attack, use that attack’s damage, but modified by Dexterity not Strength. The save DCs are Dexterity-based.
When the sonic creature is wounded, its body involuntarily makes a thunderous report. Anyone within 30 feet of a sonic creature when it is wounded must make a Fortitude save or take 1d6 points of sonic damage, be stunned for 1 round, and be permanently deafened by the sudden sound blast. A creature that cannot hear or one that makes its save is not deafened or stunned, but it still takes 1d6 points of sonic damage on a failed save. Any unattended object in the area automatically takes 1d6 points of sonic damage each time the sonic creature makes a wounding sound. The save is Constitution-based.
Spell-like Abilities: A sonic creature keeps all its spell-like abilities, but those abilities that deal acid, cold, electricity or fire damage now deal sonic damage.
Skills: As a master of sound, a sonic creature gains a +10 racial bonus on Perception checks, and it never takes a penalty on Perception checks because of ambient noise or its own cacophony. Unlike most incorporeal creatures, a sonic creature cannot move silently at will. Its body always makes a telltale humming or keening noise, which gives it a –15 penalty on Stealth checks even if it is stationary. If the base creature has a bonus on Stealth checks due to coloration, the sonic creature loses that bonus.
Special Qualities: The sonic creature retains all the base creature’s special qualities that do not require corporeal contact with another creature and gains the no breath universal ability.
Advanced Bestiary, Copyright 2014, Green Ronin Publishing, LLC; Author Jeff Hersh, Developer Owen K.C. Stephens