Making players — and by implication, their characters — feel as if they are in over their heads is the hallmark of a savvy GM. Especially for your horror-themed game session.

It also takes players who are willing to buy into the moment — the payoff comes when the sick feeling in the pit of the stomach starts churning.

Creating that moment of dread requires more than dropping a dragon on your players’ doorstep. That’s just providing an insurmountable foe. While daunting, it doesn’t capture the same feeling of fright as when suspense intersects with the monster’s appearance.

There’s at least one other problem with the dragon on the doorstep:

At least in the old days, when the GM rolled a 100 on their home-brewed wilderness random monster chart, the PCs at least had the opportunity and the wherewithal to opt out. When you see that dragon circling overhead, you knew it was time to run, hide or fight and die.

In today’s environment of scaled encounters and challenge ratings, the PCs will likely think (and probably rightfully so) this is a monster that can be overcome. Disabusing them of that notion — while at least playing fair — requires more groundwork on the GM’s part.

In the film “Jaws,” for instance, that classic moment comes when Sheriff Brody has just seen the shark for the first time, backs up away from the edge, and says, “You’re gonna need a bigger boat.”

And that works, even though director Steven Spielberg informed the audience through other means what a monster this shark was. Quint and Hooper knew their boat wasn’t big enough — they all but said so earlier, through descriptions of the attacks and, in Hooper’s case, in a clinical description of the shark’s capabilities. But it takes Brody — whom the audience identifies most because he’s the landlubber — to make the grim realization. That’s horror. Now, we’re scared.

(Spielberg pulls the same trick again in “The Lost World: Jurassic Park.” You know just by looking that the stainless steel trailer’s not big enough to protect the expedition from a T-Rex — and you’d be right. But it gets scary when the trailer is hanging over a cliff.)

In both cases, the payoff is achieved because the director foreshadowed the event. And that’s it, in a single word. Foreshadow.

Why do we know the “Jurassic Park” velociraptors will be the most dreaded beasts loosed on the island? Because we saw them devour a man in the opener, watched Grant bully a kid with fossil of one of its claws and then watched them take apart a cow before lunch. The moment that happens, you should be thinking: “If they should get out of their cages, it’s going to be really, really bad.”

And the dread comes when a hobbled Sattler must run through the gauntlet of raptors to the blockhouse, and you see her remembering what happened to that cow before it got turned into hamburger.

Let the players know it’s coming. The horror isn’t the surprise. It’s not a dragon on the doorstep, an unexpected guest with sharp teeth that belches flame and has a hankering for something more substantial than mutton. It’s knowing full well that something bad is on the way, and despite your meager preparations, you can’t do anything about it.

You might say that’s the definition of tragedy — and you’d be right — but only if the principals (say, the PCs) all die horribly and unjustly. (It’s only tragic if all the players roll a 1 in the finale.)

The monster is known — and justifiably feared —for its power and appetites.  In D&D there are literally TONS of monsters that are known to the players that have the potential to be awesome adversaries in this kind of adventure. Pick one, and start thinking of ways to build suspense around it. Then let the PCs know what they are facing up front.

The horror isn’t the monster. It’s the realization that for whatever reason, the deck is stacked against the players. As their tools prove ineffective, as their confidence erodes, as their hit points dwindle away, when their “boat isn’t big enough,” then you’ll know it’s time to spring the monster on them.

When the players, finally, have no where else left to turn or run, they’ll have to face that fear.

And roll high.