This is it, the evil warlord stands over the mountain looking at you from above, defenseless after his army was defeated; however, with a grin on his face. In a matter of seconds, a ginormous moon rises behind him, intensely shinning with a crimson tone. It is blinding and occupies a great part of your sight. As it continues to go up, you can see it dripping liquid, as if the moon was bleeding, leaving a trail across the floor. When it is about to reach the warlord, his lips start moving, saying some incomprehensible gibberish. The moon stops moving, all crimson liquid bathing your enemy as the great sphere starts to lose its tonality. His body twitches, his muscles grow, gaining about three more feet in height. Two horns start appearing in his forehead. Roll for initiative.

Some time ago I read a comment somewhere around the internet about having a blood moon appearing once per month in your game. That way, you can have chaotic and unpredictable things happen every once in a while as a consequence. After some thought, and having compared it with the one from The Legend of Zelda Breath of the Wild, I began to write some ideas down that I’ll pass to you.

An omen

The blood moon is a common occurrence that happens every X amount of time, or maybe every 2nd day of the month. Everyone in the hamlet knows it is an omen of terrible happenings, and that’s why at 18:00 those days they make sure to close all the doors, put out the lights and cower inside their homes behind great amounts of locks.

Blood moons and other occurrences are a really fun and sometimes creepy way to make your players know something big can happen. If you were to place something like this in your calendar, your villains will machinate their evil plans to happen on that date; or strange happenings from the forbidden god could appear.

On the other hand, it could also be used as a good omen. An aurora in the skies means that if a corpse was to be placed over a pedestal in the ruined temple, it would come back to life! Crops start growing faster giving a great joy to all townsfolk. Even angels come to visit the material plane for some reason during these days.

Consequences

These strange occurrences only last for a while, but you need to make them count! Let’s terrify the players, or make them want that moment to last a bit longer. For these, think about something you might consider a miracle, or maybe impossible. We are playing in a fantasy world after all, so anything can happen if you as a DM allow it. Want to scare them? Raise the dead from the last ten years for one night, or make a tornado appear from nowhere. Maybe it’s some strange occurrence that makes all the dragons go wild for a day, or resurrect the people that died in the past week.

You want to go even wilder? Portals to another plane open sparsely throughout the kingdom or continent; newborns transform into weird alien creatures. Vampires come out looking for pray! Heck, you could even throw a meteor shower if you feel like it.

A disruption in the planning

The players know that travelling from point A to point B takes a month on horse. If they were to travel this way, they will have to deal with the blood moon at least once. Do they want to take the risk? Or do they prefer to spend all their gold pieces for a peaceful voyage by airship?

The villain was discovered, but for the demon lord summoning to happen, she needs to be on a specific place during the purple night (you can easily replace this happening with another one of your choice, just like I did with the blood moon in the previous examples). The players know of this information, so they need to prevent the ritual from happening while the villain tries to delay their arrival or create traps to stop their interference.

An anomaly in the weave

If you are playing in the Forgotten Realms setting or some variation from it, the magic in your world is justified because of the existence of the weave. In some way, magic has a scientific explanation. But what would happen if every now and then the weave starts working strangely?

If you’ve read anything about the Wild Magic Sorcerer class, you will see that magic can be really chaotic. Imagine if those wild properties from the magic were applied to the whole world once per bimester. Scientists will make sure to never prove their experiments on these dates; players will try to plan attacks (or not) to have more positive results; even commoners may try to do something such as take revenge on another family creating a ruckus in the little town.

If you want to make it even more significant, you can say that every month the weave of magic starts moving strangely for a whole day. This makes spellcasters able to cast spells with a spell slot lower than the one needed (except for 1st level spells turning into cantrips because that may break the game too much imo). For example, the fireball spell can be cast with a 2nd level spell slot during that day. Want even more fun? Make every spell cast have a 1/10 chance (roll a 1d10) of targeting the wrong creature (yeah, even for self targeted spells).

Some other examples

Did you like this idea but don’t really want the occurrence to be a blood moon? I’ve got a full list of other options you can use:

Aurora borealis.

Symbol or face on the moon (a la Majora’s Mask).

Sky turning into a strange color (red, green, purple, yellow…).

Pixies or other fey beings appearing all over the place.

All things in the world, or an area changing color.

Animals acting strangely.

The weave turning visible.

Spores start floating around, each with a different color.

A night that lasts for an entire day.

Conclusion

If you want to add a bit more of fun and chaos in a strange way to your new campaign, try this out! It not only opens lots of opportunities for the DM, but for the players too. You may find a lot of fun finding out ways to interact with it, or seeing your players scared while marking each day passed in the calendar.

Have you ever had strange occurrences like these happen normally in your campaign? Did you think of anything else that could be added to this idea? I would like to hear about them in the comments!