So today is the much awaited Friday the 13th. Many of us have often wondered what it would take to put a character like Jason Voorhees into an RPG. Now there are some RPG's like Call of Cthulhu that can handle this sort of thing, but sometimes the GM wants and unstoppable evil force that requires the PC's to do more than hack and slash at the problem.
So thinking it over, here are some basic rules to help you in any game where you want a "Walking Horror" to troll the PC's.
One thing to remember is that a Walking Horror is often unique in some way, often in appearance to some degree, and they often have a favored way of injuring/killing PC's/NPC's. Additionally they all have some sort of backstory as to why they are doing what they are doing.
RULE 1: UNKILLABLE
Unkillable is the lesson here, or at least not in any traditional sense. Simply put the creature is immune to any normal means of dealing damage...to a degree. Basicly reducing their health/HP/etc. will only serve as a means of temporarily incapacitating them.
But what if your players use that chance to dismember, chain up, or in some way permanently (or so they think) incapacitate their foe?
This is where some dirty deeds come into play. First off the creature always has what you would call a "respawn" point. When incapacitated or "killed" the body (and/or its parts) all vanish once no one is looking, even if it's for a fraction of a second.
However taking it alive and keep it from killing people takes effort. This is one method of defeating such a creature...for a time.
As for damage it may take, but it isn't killed by it; that is handled in a very simple manner. If it loses an arm it can pick it up and put it back to the stump and it will reattach. The actual health lost however completely regenerates after a minute, or once combat has ended. The evidence of the damage inflicted will often remain visible on the body until the creature can return to its spawn point to rest.
RULE 2: STAGGERING POWER
Walking Horror's have an unbelievable degree of power aside from their resilience against truly dying.
First off the creature should possess strength above and beyond any normal being. They can break through doors with ease, shove weapons completely through very solid objects like sheet metal, trees, and so on. They are not overtly agile or greatly coordinated however, (which works in favor of the PC's), but this should not discount from their lethality if they do hit.
Now having staggering power doesn't mean they spew fire or shoot lasers from their eyes. No this is all about brute power in killing and even a glancing blow can be staggering and leave a person open to a finishing strike.
On the other hand a supernatural ability to doggedly track a target or even to follow them at an slow pace compared to them and yet still manage to keep pace with them is another common factor. Now just because the creature locks onto a person doesn't mean they can't be fooled or hidden from. It's just that when they have a target they are focused on they receive a bonus to their attempts to locating the target. This can be switched if someone else does something to catch their attention however as these creatures are often very focused, but that focus can switch quite easily.
RULE 3: DEFEATING THE MONSTER
Ok so lets say you have all the strengths of this thing figured out. Now let's touch on how the PC's can deal with it. For the most part in the movies characters just run away of find what they perceive to be a weak point for the creature that they exploit at great personal risk.
First off the creatures weakness often revolves around how it came to be. That is to say that if the creature drown back when it was alive then it has an unusual weakness to drowning...but on the other hand it spawns from a lake to go out and do its killing. So drowning it is a method of defeating it, but it's likely a temporary solution.
And that's often how it is with many Walking Horrors. The means of defeating them is only temporary at best.
So how do you put one down for good? Well that is a bit more labor intensive. As the GM you can come up with a fairly complex method of doing this, and the creature will know when people are attempting to kill it for good. Now going back to our lake example, to kill the creature for good you would have to get rid of the lake, that is where it spawns from, and if it has no method of spawning (and yes it's also possible that other methods could exist too) then it becomes vulnerable and thus killable.
But what about getting it in chains, putting it in a cement black and leaving it like that? Sure that would work...but it's not permanent. You could buy yourself years or decades, but eventually it will get free as the powers that be that gave it life can still work in its favor, such as it constantly straining against the cement and chains to eventually cause cracks to appear and for metal to warp.
Now the movie monsters don't typically have a means of permanently dying regardless of what's done. But that doesn't mean that this has to be the case for your game and its monster. Players need to feel a sense of accomplishment when they defeat this creature. So having all of their hard work being for nothing is a kick in the gut.
But what sort of XP or reward do they get for succeeding?
Well again that's up to you. Obviously the creature represents a significant challenge and should reap a reward that shows how significant that is. One good method of this is looking at the parties level, or the overall challenge of the situation and increasing what the reward would normally be for the overall encounter by possibly doubling the rewarded XP (or similar reward).
That should do it for now. I hope you all find this helpful.