Skeleton with a bow

I was playing Castlevania and thinking of fun encounters. It got me thinking...

A skeleton in B/X is a 1 HD monster, maybe with 4-5 HP - relatively weak, unless you find half a dozen at once (which is likely).

But picture a skeleton with a bow in a place you cannot access easily - a tower, castle wall, or behind a chasm or river. Maybe you could climb it in, say, three rounds, less if you're a thief.

Now let's give him some resistance to arrows, since it has no flesh or organs. Maybe arrows do 1 point of damage to it at most (or half damage if you don't want to be mean to archers).

And put him in armor. To evil wizards, they are better than mercenaries, since they require no food, sleep, pay, or overtime. No morale checks either.

He is now a bit of a challenge to a group of first-level PCs by himself.

You could use turn undead if you have a cleric. That is, if there is no range/area limit.

But throw a robe over the skeleton and maybe the PCs are not even sure what they're dealing with - until they get close!

Now put ten skeletons with robes and armor over the wall an this becomes a challenge to a level 5 party. We don't even need to raise HP. 

A fireball might explode one of them - they are scattered. Charm, hold person, sleep, etc., are all useless here.

Arrows are of limited use, but slings and magic missiles get a chance to shine (even if a longbow has slightly better reach). The thief gets to use his climbing skills in an action scene - maybe even moving silently in the process while his allies take cover.

Come to think of it, is it fair that the skeletons can "see" the PCs? Well they are probably programmed to shoot at anyone who comes near the castle or try to cross a bridge.

If they run out of arrows - they probably only have a few - they might climb down the walls (sounds reasonable but the armor might make things difficult; some may fall and be destroyed in the process, which is a cool scene by itself).

And when the PCs find out what is happening, then the evil wizard unleashes the Bone Golem, to see all the usual tactics (turn undead, fireball and lighting bolts) fail spectacularly.

Sounds like a fun game to me!