Every city that has ever existed has had a pest problem, because where there are people, there are creatures that survive on what we leave behind.

Now most cities have rats and cockroaches, perhaps squirrels and pigeons depending on how generous you’re being. But your city is going to be different.

Your city is going to have spiders. And not those boring spiders that just make a web and sit there and wait for something to wander in. These spiders are going to hunt. They’re going to crawl across the city, lurking up on the walls and in the alley, ready to pick off any jaded urbanite who thinks they’re safe just because they’re not in the wild.

The Giant Wolf Spider is truly underrated as a predator. It moves quickly, either on flat land or up along the walls, and its bite can deliver a nasty payload of poison. It’s incredibly sneaky and perceptive, and while it’s not terribly intelligent, its Wisdom score is high enough that it could fairly easily anticipate its prey so as to better hunt it down.

While it may not be a terrible combat challenge for most parties higher than first level, that doesn’t mean you can’t use it to instill absolute terror in your Players. Your Players, you see, are used to being in charge of the story. They are the ones who seek information, who hunt down monsters, who slay terrible threats.

With the Giant Wolf Spider, your Party is being hunted. Imagine them, slipping in and out of sight silently as your Party walks tours the city during the night. In this neighborhood, people have stopped going out after the sun goes down, locking doors and windows against the terrible, silent scurrying monsters that – according to rumors – have already carried off some of the more fragile members of the community. Not anyone anyone actually knows – a friend’s sister’s neighbor’s grocer’s ex-husband said he’d heard about it, though.

Rumors aside, that doesn’t mean they’re not a threat. The bite from one of these Spiders could easily kill a Commoner, to say nothing of their children, pets or livestock. The residents of this neighborhood know how to deal with the usual infestations of a city, but creatures like this are beyond them.

From here, you just have a few questions to answer and the scenario reveals itself.

Where did they come from? Perhaps an ambitious Giant Spider from beyond the city limits followed the rats, seeking a source of food that is reliable and plentiful, as rats in the city often are. Once there, the Spider discovered a place wholly unprepared for it, and so the Wolf Spiders created a niche of their own. Or maybe they were brought to the city. An enterprising Wizard wanted to enchant them to do his nefarious bidding. An Urban Druid thought they would be a great way to control an exploding rat problem. The city’s gnome watchmakers had a fad for exotic mounts, and the Spiders were most popular.

However you choose to get them into the city, they’re part of it now. Which brings us to the next question: What is the city doing about it?

Naturally, people don’t want to go out when there are Spiders the size of large dogs lurking about, waiting to pounce. The City Guard will no doubt be called in to deal with these things – but can they? Maybe individual Spiders sure, but these are hunters. They observe. They predict. They hunt in packs, funneling their prey into tiny alleys where their brethren lurk, and any City Guard who thinks themselves more powerful than a Giant Spider will soon learn otherwise.

It sounds like the Spiders aren’t going away anytime soon, so How will people live with them? There’ll definitely be a class divide emerging here. The wealthy will be able to pay for methods to either kill or repel these Spiders. Arcane wards or carefully-crafted fences might keep them away from the wealthiest homes, meaning the Spiders will focus on the more vulnerable. Perhaps, with the City Watch proving ineffective, gangs of volunteers will go out, hunting these creatures down and destroying their eggs.

Fun fact: Wolf Spiders carry their eggs with them. This might slow them down, but it might also give you the opportunity to release a number of Swarms of Spiders when one is killed. Feel free to keep adding spiders on spiders until your Players go utterly mad.

If you’ve really built up the environmental horror of these Spiders, your Players will be more than excited to hunt down their nests and destroy them. They can collect a hefty bounty from the city or a citizens’ association, and maybe sell poison sacs or spider silk to local merchants.

Of course, depending on how long the Spiders have been around, destroying them will have ramifications of their own. The rats and squirrels and pigeons will re-emerge, causing their old chaos again. Maybe a conservationist group has emerged, seeking the recognition of these Spiders’ right to live, challenging your Player’s knee-jerk desire to kill the poor, misunderstood arachnids.

And maybe – just maybe – these clever hunters were actually hunting something far worse than local vermin. Perhaps they had got a taste for something truly chthonic and terrifying, and it was only they who were able to keep it at bay. With the Spiders gone, this thing has the freedom to show the residents of the city what true horror is.

Like so many of the Beasts in the Monster Manual, they have a place in the world. The Giant Wolf Spider is a great way to experiment with putting them in new places, places that are utterly unprepared for them. And if you can create true, spine-tingling horror with a pack of these guys, imagine what you can do with the other inhabitants of the Monster Manual at your table.