Skeletons - they live within us all
There are many common low-level mooks; goblins, kobolds, orcs, rats, etc. But there is one that I think stands the test of time far better than those and that is the humble skeleton. Why? Because they are a part of the collective consciousness. Every culture on earth has seen a skeleton and has tales and images of death. Not every culture has a kobold. Since time immemorial, the skeleton is a sign of human mortality. But in our elf-games, the skeleton is, as I've said, a low-level mook. Is this fair? Perhaps. But there is an urge within to give them more than that, probably because of what is my third-favourite special-effects sequence of all time, the skeletons in Jason and the Argonauts by Ray Harryhausen. (The first two spots are reserved for the Kali statue fight in Harryhausen's Golden Voyage of Sinbad, and the opening of the Ark in the first Indiana Jones).
The Jason and the Argonauts skeleton fight is my go-to image of skeletons. They're dangerous. They're kinda goofy. They're jerky in their movements - is it because of necromantic energies that bind their bones or is it because that's as good as claymation in 1963 is going to get? How do we capture the Harryhausen skeleton in the context of an OSR game? How an we improve on the simple tried-and-true skeleton without radically changing it or making it so powerful that it loses its charm and usefulness as an easy encounter for fledgling adventurers? To determine this, I shall be providing a description of both Harryhausen skeleton scenes, that in Jason and the Argonauts, and the single skeleton fight in the Seventh Voyage of Sinbad.
First, Sinbad, as it is a much shorter scene. A skeleton drops down from the ceiling and slowly lumbers awake as it is being controlled by a bald sorcerer. It marches over to the armoury and once it receives the command to kill, arms himself and the fight begins. The skeleton displays a degree of cunning and intelligence; when it is disarmed, it causes a distraction so that he may pick up his sword. It attempts to gain the high ground on a staircase (which ultimately leads to his down-fall). It, when faced with a seeming defeat, looks about for routes to escape.
What does this tell us? While yes, he was under control of a sorcerer, at least via the command to kill, he was not a mindless drone performing a pre-programmed set of actions - he was a thinking foe capable of altering his plans on the fly..
Second, Jason and the Argonauts. The skeletons grow out of the ground, coming to attention before being commanded to kill by a fellow with a silly beard and even sillier toque. Clearly an evil sorcerer. As they slowly march forward, the heroes slowly back up, clearly unnerved by the events. The skeletons let out a scream, odd for an enemy that is usually depicted as silent (other than the odd note of bones rattling), and the heroes retreat. Again, they show intelligence as they manage to split the party so each smaller group of skeletons only has to deal with a single combatant. As well, they pause and wait for an opening before they strike. In their fighting, they are quick but also clumsy, often falling over or being thrown to the ground before hopping back up and re-pressing their attack. Skeletons are stabbed and yet they continue to fight on. It seems only after they fall from a fair height (as was the case in Sinbad), can the skeletons be destroyed.
Our observations? As above, as well as a natural defence against spears and blades, a fearful aura, and a method to destroy them - having them smashed to tiny pieces.
So with those observations, we see how we can alter the skeleton. Add a sorcerer who controls the skeleton. This adds an additional dynamic to the battle as whoever controls them will also be working against the party (though in both films, the controller took a back seat to the fight). Make them smart - they should hound the party with hit and run tactics, separate them, use the environment to their advantage. Of course, most monsters should be doing this unless they are mindless automatons, as skeletons are usually presented.
What of fear? The single skeleton in Sinbad lacked this, but the host of skeletons in Jason exhibited it. Therefore, the fear aura of a skeleton requires a certain HD threshold before it can activate. Now, that could be 8 normal skeletons, or 4 normal skeletons and 1 4HD skeleton who is the 'leader' or whatever you want. Choose a number and stick with it.
And damage resistance - being smashed from a large fall is essentially using the earth as a bludgeoning weapon. Giving skeletons DR vs slashing and piercing weapons is common in the modern era as was it in AD&D1, though not in Moldvay Basic. I do not like simply giving them DR. It is a boring solution. What I propose is this: when you destroy a skeleton with a mace or hammer or similar weapon, they are crushed. When you destroy a skeleton with a sword or spear, his bones scatter, only to crawl back together and reform, continually until they are turned or crushed. This makes them scary, it fits with the idea of them being less vulnerable to bladed weapons, and it brings with it a certain air of the Evil Dead or Addams Family; that slight twinge of comedic relief as the bones crawl around searching for each other that the flopping-about skeletons of Jason and the Argonauts exhibit.
Is this too powerful? Two of the changes involve adding more combatants, making it appropriate for deeper levels of the dungeon when the players should be more than capable of handling such issues. The third change removes the 50% damage reduction in AD&D but adds an infinite-respawn until properly destroyed, similar to that of a troll with fire or acid. It is not un-reasonable, therefore, to introduce such a measure. It has precedent within the game, though with a much more powerful creature. Especially with this change, not only is the power of a skeleton increased, therefore instilling fear and excitement in your players, but the image of the skeleton is changed; no longer are they waves of bones that can be swatted aside with a single sword blow. They are now a relentless force of evil, that require wits to defeat.