They come screaming, jabbering, and howling out of the night. Dozens, maybe hundreds, of hunchbacked, naked humanoids swarm unceasingly forward, brandishing short swords. They have no thought of safety, subtlety, or strategy, leaving others with no hope of stopping their mass assault. And then, having come and killed, the gibberlings move on randomly back into the night.
The first impression of gibberlings is of a writhing mass of fur and flesh in the distant moonlit darkness. The pandemonium is actually a mass of pale, hunchbacked humanoids, with pointed canine ears, black manes surrounding their hideous, grinning faces. Their eyes are black, and shine with a maniacal gleam. They carry short swords in their overly long arms as they lope ever faster forward.
Gibberlings attack in great numbers, uttering ghastly howls, clicks, shrieks, and insane chattering noises which cause even the boldest hirelings to check morale each round. PCs need only make a morale check if it is appropriate to their character. The screaming mob is completely disorganized in form, and random in direction.
The gibberlings attack with common swords, but such is their skill and practice in using these weapons that they are +1 to hit. Their forward motion slows only long enough to kill anything moving, then continues forward, their bloodlust apparently unabated. They always fight to the death. All food in their path is devoured, including the fallen among their own number, and any unfortified building or objects are generally wrecked.
The only true hope of survival, should a herd of gibberlings be encountered, is to take strategic advantage of their fear and detestation of bright light. The gibberlings generally frequent only dense forests and subterranean passages, loathing bright light of all kinds, and are particularly afraid of fire. Although their mass attacks would quickly overwhelm someone wielding a torch, a bright bonfire or magical light of sufficient intensity will hold them at bay or deflect their path.
It is difficult to imagine a gibberling social structure. It can be roughly compared to the social structure of lemmings throwing themselves into the sea, or of a school of pirhana in a feeding frenzy. There is no sense, no organization, and no individuality. Though they clearly have a primitive means of communicating among themselves, they have no discernable language.
Gibberlings traveling above-ground invariably burrow into the ground to hide during the daytime, and it is at such time that they are most vulnerable. They can easily be tracked by the path of chaos and destruction they leave, and can be quickly dispatched while they lie dormant just beneath the surface of the ground. If uncovered, they awake, but generally cower in fear at the bright light surrounding them, and so are easy prey. Subterranean gibberlings may burrow into the ground, or may simply lie down in a curled, fetal posture at times of rest. They awake suddenly, as a group, and burst in unison out of the ground, howling and gibbering in a most frightful way.
If captured, these strange creatures speak only their own incomprehensible gibberish, and show neither the patience nor the inclination to learn other languages or communicate whatsoever with their captors. Instead, they beat against their cages and fling themselves at barred windows and doorways in pitiful attempts to escape their captivity.
It is unclear how or when or even if gibberlings procreate.
Attempts to find the gibberlings' lairs have inevitably led back to subterranean passages, where the trail is eventually lost in the deepest rock-floored recesses of the caverns.
Gibberlings require a prodigious amount of food to support their manic nocturnal existence, stripping to the bone anyone or anything that should fall in their path. Their fur is commonly infested with lice and other pests picked up during their burrowed slumber. Their hides are vile and worthless. Gibberlings carry no treasure or other useful items.Their swords are of the commonest variety, with no markings or decoration, and are often pitted and dull. In short, gibberlings serve no purpose and no known master, save random death in the night.