Looking for quick, evocative weirdness to spark a session? 1d100 Space Anomalies is a fast way drop-in encounters for Mothership, Stars Without Number, or any sci-fi game. Roll a d100 between scenes, during travel, or whenever you need a curveball. Use it as a prompt, a hazard, or the seed of an entire scenario.
How to use it:
- Roll 1d100 and drop the result straight into play.
- If you’re mid-session, pick an entry that fits the current vibe.
- Many results imply follow-up clues like signals, ruins, psychic echoes, and more. Treat those as breadcrumbs to your next encounter.
Below are 15 sample entries pulled from my full 1d100 Space Anomalies list. Grab the complete, formatted PDF (all 100 entries) free via the signup block further down.
- A star that suddenly dims and brightens in a pattern that suggests it is sending a message using a universal mathematical language.
- An ancient cargo vessel, drifting between stars, its cargo long since looted but still guarded by automated defense systems.
- An asteroid emitting a signal that, when decoded, appears as a series of disturbing, surreal images.
- An interdimensional fissure that occasionally spills objects from other realities into our own, ranging from mundane to highly advanced.
- An orbiting array of mirrors around a desolate planet, focusing sunlight to create a habitable zone on an otherwise frozen surface.
- A mysterious void in space, appearing as a perfect black circle. There are no gravitational readings, but anything that enters disappears completely.
- A ‘sleeping’ black hole that sporadically emits pulses of light and energy, waking up to consume nearby matter before falling dormant again.
- A star with a visible fracture-like feature on its surface, leaking solar flares in unusual patterns.
- A series of floating obelisks, which when aligned perfectly, reveal the location of an ancient, advanced civilization.
- A pulsar wind cast off from a long-gone supernova corona. A massive planetoid is being pushed along in the current.
- A cloud of iridescent gas that subtly alters the color spectrum of any light passing through, creating surreal visual effects.
- A gravitational force that generates a low humming through the ship. Sensors and scanning devices suddenly become useless.
- A derelict warship, its weapons still operational, floating near a strategically important trade route.
- A spatial rift that emits a spectrum of light invisible to the naked eye, but with the profound effect of enhancing or dampening emotions.
- A planet-sized quantum computer orbiting a forgotten star, solving unknown equations and occasionally broadcasting its findings into distant space.
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Related Resources & Next Steps
- Pair these anomalies with jump-space encounters from 1d100 Interstellar Encounters (on our store or DriveThruRPG) to build a complete travel chapter.
- External link: Curious about megastructures that inspired entries like Dyson spheres? Check out this article on Space.com for real-world science musings you can fold into play.
- Getting started with sci-fi: For running futuristic campaign, see this blog post over at Follow Me And Die.
GM Tips
- Escalate on repeats: If you roll the same anomaly twice, advance its “story.” The mirror ring fails; the void swallows a probe; the soul nebula asks for a favour. Ramp up the result in new and interesting ways.
- Breadcrumb clustering: Place three anomalies in the same sector and connect them. For example, your players could discover an errant planetoid caught in an interdimensional fissure, along with an ancient cargo vessel.
- Faction hooks: Integrate into your campaign by leveraging your existing plot points. If megacorps are causing havoc with private armies, they could be extracting them from the phenomena. If a cult is expanding their territory, they could be worshiping an aspect of the deep space feature. Your crew is stuck in the middle.
Happy voyaging. And may your jump calculations fail in the most interesting ways.