The now-extinct northern Dwarves were not natural magic users, but they were very capable in crafting magical effects from various rare ores. This extended to giving life to various pseudo-mechanical creatures and beings, and even to giving life to assemblies of flesh. An unhealthy competition arose between various lords as to who could create the most dangerous guardian for their palace or home. One of the most feared, by legend, was the Guardian of the Palace of the Perfect Moon.
The physical appearance of the Guardian makes no sense; such a thing cannot be alive. And yet it is. An eight foot tall pillar of enchanted flesh, with four great leonine heads. One sits at the top of the pillar, and has skin the colour of gold coins; two more sit beneath it, silver coloured and side-by-side. Beneath those is a head the colour of rust, eyes half-closed. It stomps around on two big thick feet, leathery pads slapping on the floor. It does not sleep, it does not tire. It is ageless and needs no sustenance. It only lives to stop people from passing it.
The Guardian of the Palace of the Perfect Moon
AC as chainmail. 7 HD, two attacks (each attack gets +3 rather than overall +7). See below for magic attack.
The silver heads attack targets in front of them, extending forward a little on thick necks. A successful bite attack does d8 damage.
Every four turns the gold head casts a spell (roll a d4 to pick between Darkness/Sleep/Magic Missile/Stinking Cloud); attacking the head cannot stop the spellcasting. For spellcasting purposes it casts spells as a fifth level Magic-User.
Attacks called at specific heads do not suffer a penalty. If any head takes more than 10HP of damage then it is dis-oriented and cannot attack for 2d4 rounds. The Guardian does not sleep, and is not fooled by invisibility spells.
Notes from Play
The party fought the monster in a regular 10 feet wide dungeon corridor; they were able to form two ranks, but only one person in the rear rank had any kind of range weapon. They had had no warning about any particular monster, and were not expecting what they faced. They were surprised by the spellcasting of the gold head the first time. During the fight The Guardian got two spells fired off (Magic Missile and Sleep, both of which seriously impacted the fight). The party consisted of two PCs (fifth level Specialist, third level Fighter) and four NPCs (effectively two first level fighters, first level cleric, second level fighter). Both PCs took a fair amount of damage, two of the NPCs almost died and another one was reduced to less than half HP. It felt like a hard-won fight on their part. A high point in the session!