Crawl of Cthulhu – Introduction

Essential investigator tools for a crawl. Image by Petri Damstén.
©TSR, 1981

Call of Cthulhu entered the roleplaying world in 1981, during the golden age of dungeon crawling.  In the same year, TSR released the module entitled In the Dungeons of the Slave Lords (A4), and The Keep of the Borderlands (B2) had already thrilled fledgling adventurers for two years. While Chaosium’s new creation unleashed the potent combination of investigation and horror, a few early adventures leaned on established conceits born in fantasy roleplaying, including the dungeon crawl. The 40th anniversary of the game brings us the reprinting of the second-edition core rulebook, as well as a collection of early game supplements, including The Asylum & Other Tales and the Shadows of Yog Sothoth campaign. Between the rulebook and the two supplements, Keepers gain access to these three classic Cthulhu crawls “The Brockford House” (2e rulebook), “Black Devil Mountain “(Asylum), and “The Warren ” (SoYS). Sadly, some of this rich material fails to fully capture its potential. For example, “The Brockford House” provides a two-story home for investigation with really only one or two findings of useful scenario significance spread over nine rooms As usual, the investigation really takes off in the basement, but why waste all that real estate?

Bringing these old gems up to contemporary gaming sensibilities allows Keepers and new players to savor a bit of the old-school flavor. To do so, we take the scenario scaffold, including maps and basic plot elements, and then add the following key crawl elements to stimulate investigator interest, action, and intrigue.  For the purposes of discussion, we refer to individual locations as rooms. 

A classic collection with a great dungeon crawl scaffold. ©Chaosium Inc., 1983. 

Designing a Cthulhu Crawl:

    • Clue (Skill Challenge, group, or investigator spotlight): the bulk of the investigative work takes place in clue rooms, where players employ their skills to obtain useful information to further their investigation or clarify the plot. Common investigator skills like Listen, Spot Hidden, and Library Use allow pooled resources. Selecting a focused skill challenge, such as deciphering old tax records (Accounting).
    • Obstacle: similar to above but instead of a clue, the reward is continued progression through the environment, useful to provide alternate routes or various solutions to avoid bottlenecks.
    • Interaction (NPCs): Provides another avenue to offer up Clues, stimulate intrigue, or encourage roleplaying during the hunt for information.
    • Progression or Escape (Passage): Successful application of a Clue, combat, or roleplaying opens a new passage, such as a trap door or sliding panel, allowing movement past an Obstacle or progression to a new location in the adventure. Alternatively, this allows escaping from a threat near the conclusion of the adventure.
    • Trap (Sanity Loss): player walks into a room seeking clues and finds a corpse in a closet, a disturbing work of art, or a glimpse of something from beyond. Using Sanity Loss for traps establishes the Cthulhu tone, but, if you want to increase danger, set physical traps to be dodged, disarmed, or destroyed by suitably paranoid or lucky investigators. 
    • Treasure (Useful Item or Free Clue): as simple as a flashlight or as critical as a specific item required to defeat the Mythos threat. Tailor this to accommodate the obstacles investigators face in the crawl. Alternatively, offer an easily accessible clue to facilitate further exploration. 
    • Wandering Monster (Lesser Mythos or Human Opponent): maintain thematic consistency, and avoid random collections of Mythos creatures (“a Shoggoth in every adventure”). The rate and frequency depend upon Keeper’s discretion. Consider setting a percentage with increased risk with each room or by room or allow investigators to determine fate with their failed Pushes and Fumbles or called Group Luck rolls. 
    • Boss Fight (Mythos Encounter): key to most scenarios, and typically encoutered near the conclusion, but potentially hunting Investigators from behind creating a sense of pressure (think Alien’s xenomorphs or shoggoth in Mountains of Madness).

Some of these categories easily overlap, in particular, both Traps and Treasure pair well with Clues. Defeating Wandering Monsters or Bosses also offers sources for Clues and Treasure, as well as opportunities to Progress/Escape

The greatest investigator treasure? Or a trap?

As you fill out your locations, strive to make most rooms interesting in some way. Even if the room doesn’t contain a threatening or helpful element, provide a thematic feature of interest by offering Flavor to encourage roleplay, like an annoying dripping faucet, unusual furnishings, or shadows cast from the tree outside. Strive to play on all the senses. The rare empty room with a musty smell and think layer of dust still evokes a mood and raises suspicions despite offering no clues. 

Taking a bare map of a house, cavern complex, or ghoul warren and quickly stocking it with a thematic combination of these crawl elements provides Keepers with an easy method for fleshing out an intriguing scenario. In our next post, we apply these elements to “The Brockford House” to provide our players with a juicier mystery to sink their teeth into. After spending some time with a few classic scenarios, we turn our attention to bringing dungeon crawl elements to Masks of Nyarlathotep with a focus on Australia and Egypt.

If looking for additional Cthulhu crawls, we first recommend Christopher Smith Adair’s Darkness Beneath the Hill” from Doors to Darkness, which is excellently crafted for contemporary tastes.  The 1990 4th edition supplement Fatal Experiments provides three linked scenarios set in the 1920s. Both The Songs of Fantari and The Lurker in the Crypt provide crawling opportunities. The book also contains some really neat material on unusual weapons. While Songs offers a light and abbreviated crawl, Lurker truly leans into the genre with a fantastically wild collection of maps taking investigators on a deadly journey beneath New York City. This adventure extends beyond the intended scope of this article but absolutely demands some future attention.