Hello there fellow ex-DM academy scholars,
Just left Reddit for good, so I'm here with a question that wasn't answered in under spez's shadow, so I might try it here if I can.
I would like to know if you know of magical items or spells for 5th or similar that would attract ghosts and other spirits : ghosts, banshees, souls, etc.
I would like to take example from an existing item for what I am preparing in a currently used dungeon that I made.
I don't know of any official items that draw in ghosts and spirits, and also just to ask, do you mean summoning them on use like "when you blow this horn, 2d6 ghosts are summoned" or do you mean it like a passive effect, like "Curse. Ghosts and other wayward spirits are drawn to this item"?
Second one. Its part of a dungeon that is more or less a flytrap of souls for a Liche to feed its phylactery. One of the room will include unfighting ghosts attracted to an orb that acts as a light to moths for them.
For artefacts that have little no to no PC use in combat I worry very little about balance or mechanics. Just let it do what I want it to do. Kind of a non-answer I know.
I would actually look more to lair effects and weird things from dungeon rooms for inspiration in this case. Don't have any on hand but it could be another avenue of research.
I am going to steal your idea though and put it in the big ol' good-ideas-that-i'll-forget-about folder.
To me, this sounds like a custom 'minor detrimental property', as seen in the DMG's guidance on creating artifact level magic items, page 220.
You don't really need specificity for this, if you look at the regional effects of a vampire for example, it reads "There is a notable increase in the population of bats, rats and wolves in the region". And that's enough of a prompt to cement that usage.
If you want to model it after an existing item with mechanics, you could create an undead version of the Orb of Dragonkind from Dragonlance. Here is it's Call Dragons ability:
While you control the orb, you can use an action to cause the artifact to issue a telepathic call that extends in all directions for 40 miles. Evil dragons in range feel compelled to come to the orb as soon as possible by the most direct route. Dragon deities such as Tiamat are unaffected by this call. Dragons drawn to the orb might be hostile toward you for compelling them against their will. Once you have used this property, it can't be used again for 1 hour.