Beneath the more ancient streams and rivers of the world form caverns, eroded away by the chemistry of stone and water. Beautiful formations of stalagmites and stalagtites grow from the dripping water and eroded minerals. On occasion, such caverns form beneath enchanted streams, ancient bodies of water full of magic. The caves these streams create are powerful in themselves and highly sought after by sorcerers and other students of magic. Aside from the usual fey creatures that dwell in magical caverns, darker beings can arise who take it upon themselves to defend these cave fiercely. In common tongue, they are known only as stalagmen.
It has long been questioned among scholars when or by whom stalagmen first came to be. Some say ancient shamans created them to protect sacred groves, others that they are as natural as any other creature, or perhaps they were even created by cthonian gods to protect the earth. Origins aside, stalagmen are regarded as some of the least friendly creatures beneath the earth. To the average explorer, their appearance is no different than any other rock formation: a simple mineral spike, either hanging from a ceiling or sticking out into the air. Even upon close inspection, one could assume it is merely a simple rock. Their subtle camoflauge hides a fierce defender. As an intruder passes stalagmen, the creatures will slowly approach from behind, making only the slightest of scraping sounds against the stone, less if a cavern is muddy. A traveler being stalked by stalagmen can easily dismiss the approaching creatures as tricks of shadow or their own imagination. By the time stalagmen are openly moving to block the spelenkur’s tracks, one may find herself completely surrounded.
At will the stalagmen reveal their true forms, dense stony limbs appearing from the mineral spikes, and angry faces forming from the stone. They often wield spears formed from small stalagmites, or attack using their mineral-hardened mouths. Unlike average cave formations, they are quite tough, perhaps from their magical nature or the rare minerals from which they are created. They are formidable if slow fighters, forming phalanx-like walls of spikes to prevent an intruder from escaping. The offender, once overwhelmed, is quickly chewed and ground into a fine mush by the stalagmen, returning their minerals to the cavern floor. If cornered by stalagmen, one is best advised to try and manuever their way over or around the creatures to escape, unless willing to take the chances of fighting the stony beasts.
Little is known of stalagmen society or physiology. It is generally assumed they are genderless, as they only reproduce by the centuries-long dripping of sacred cave water. Also unknown is if they awake while no intruders are present. Though it is generally assumed that they are mindless as guardian golems, a curious activity suggests otherwise: song. Many miners report hearing low, rumbling chants just before coming across stalagmen colonies; whether this legend is supported by fact is unknown. Suvivors of stalagmen attacks also report a gravelly language among their kind, suggesting some sort of culture. Dwarves come across stalagmen colonies with annoying frequency, disrupting mining operations and causing skirmishes among the subterranean kingdoms. The only boon of their frequency is dwarven expertise on quickly dismantling the creatures (most recommend a cold-forged steel battleaxe), and the indication of a valuable mining spot, as the caves in which stalagmen form are often rich in valuable minerals.
Any cave of significance might have stalagmen present, providing a potentially surprising encounter for interlopers. Their presence can indicate valuable minerals present, or that a particular cavern is magically important.
The King’s Caves - A local ruler recently opened a mine in newly acquired territory. Unfortunately, most of the miners seem to have disappeared. The PCs are asked to investigate. Their journey into the cave reveals a small and intensely angry group of duergar cultists who have apparently raised an impressive army of stalagmen to conquer the outer world. An army that is now aimed at the party. Defeating the duerger will stun the stalagmen for a time, but once they recover, they too will be violently upset at the invasion of their caverns. If stalagmen and all are defeated, searching the cave will result in finding valuable duerger artifacts, and a very valuable mining operation that the king will reward the party handsomely for.
Based on a Penny Arcade comic: http://www.penny-arcade.com/comic/2007/10/10/as-seen-in-modern-lair/