What to do with random tiny rune cube my player found last night?

[MonkeySage]

My player was searching through a random pile of gravestone fragments and because he scored a nat 20 on his perception, I didn't want to tell him he found nothing. So on the fly I gave him a faintly magical stone with a single rune carved into it. It's the size of a marble, and perfectly cubed. It weighs nothing, and has no useful effects by itself. I had the idea that if my players find a lot of these, always by scoring high in perception, then they'll do something neat.

So what should that "something neat" be? :P The stones look exactly like role playing dice, but only have one face carved.

[Stelio Kontos]

Single use items, with numbers for the cubic ones from 1-6 marked in magic script (read magic will do it). Use it instead of rolling a d6.

Naturally, these can be different shapes...

[terodil]

Oh, oh, so many ideas!

- could be part of a mosaiq or coded message that reveals some super-secret lore that can come in handy later during the campaign (true name of a powerful entity so you can summon/beseech it later, directions to the single-use Vorpal Sword of Slaying, ...)
- could be key parts to a long-forgotten tomb from a long-lost civilization, or to the lair of an ancient imprisoned lich with untold riches, see above
- could also be a trap (with some big pay-off, of course). E.g. take the suggestion above, with the cubes being key parts to the imprisoned lich, yet warded against abuse -- somebody wanted to make sure the lich stays locked up even if all keys are found. The trap could either be just that, a simple trap, or an adventure hook all by itself, e.g. a portal to the plane where the prison proper resides
...

Fun!

[Telonius]

Well, you could go with the Infinity Stones idea.

Not the actual Infinity Stones, but more like an Item Set (like they have in Magic Item Compendium). Each one is a specialized Ioun Stone. Each gives a neat little benefit, not listed in the standard Ioun Stone list. They only work if they're unlocked (unlocking mechanism: cast a particular spell onto them; Identify or Legend Lore to figure out what the spell is). Once the spell is cast onto them, they start functioning and flying around the user. If you have several (usually 3 or 5 pieces is the threshold), there are resonance bonuses.

[PastorofMuppets]

The first thing that comes to mind is that it’s a key of some kind. If that’s too simple for the game maybe it is a symbol that proves membership in some secret society

[Xuc Xac]

Little rune carved cube? Viking holocron.

[Jay R]

Wait until they've found several. Then they will come upon the item or wall that they fit into, to open a secret door nor activate an important action. This is why the treasures are still there -- no previous adventurers had the key.

They've found the equivalent of a Kryptonian crystal. It will become useful only when they reach the analogous Fortress of Solitude.

[DMThac0]

A lucky die, however, it's only lucky if the die lands with the carved face up. Once per (insert time frame) they get a +1 bonus to skill, attribute, damage, saves, DC, whatever. The more impact the bonus has, the more faces the die has (To hit roll is more impactful than a Skill roll, generally, so To hit would be a d10, where as Skill is d6)

[Bohandas]

The stones look exactly like role playing dice, but only have one face carved.

Whatever it does, using it is either going to make more carvings appear or make the current one disappear

EDIT:
Possibly each carving (or in this case the carving) represents a spell and the carving disappears when the spdll is discharged. Up to you whether it's one use each, gradually recharges, or is spell storing, but in any case it's probably limited to level 0 or level 1 spells if the aura is faint

[Nifft]

If they find 27 of the things they can build an Ubik's Cube, which allows them to invert time (once).

[hotflungwok]

They're baby's toys made by a wizard. They have elven runes on them, and if you put them next to each so that it spells a valid elven word, they glow green. If you put them next to each other and they don't spell anything, they glow red. The wizard and his family travelled all over the place and the little rugrat was fond of tossing his toys out of the carriage, so they're scattered everywhere. If they can find enough of them, and return them to the wizard, there might be a reward...

[weckar]

What is the game/setting? Even the difference between high or urban fantasy couod matter here. Modern? Medieval?

[MonkeySage]

Late medieval high fantasy, average magic.

[Jay R]

They could be very low-level magic individually. one alone glows when brought within two inches of a magic item, or it might perform some other utilitarian cantrip.

Perhaps with 2 of them you can perform a 1st level spell, with 4 a second level, and so on.

That makes 512 of them a way to cast a ninth level spell, with increasing rewards as you collect them.

[Keltest]

Its a small charm designed to help prevent a dead body rising to become undead. By itself it isnt amazingly useful, but it can be worked into items to give bonuses against the various flavors of undead. Maybe just possessing it gives the wielder a +1 bonus to all saves against an effect caused by undead.

[Xuc Xac]

Its a small charm designed to help prevent a dead body rising to become undead.

So if you collect enough of them, you'll end up with an army of the undead rising in your wake. Someone put those there for a reason and you're picking them up and walking off with them.

[Keltest]

So if you collect enough of them, you'll end up with an army of the undead rising in your wake. Someone put those there for a reason and you're picking them up and walking off with them.

Exactly! All sorts of interesting things can happen!

[Cealocanth]

It might be archaeological find. A pilgrim badge from an old Dwarven religious shrine. Most of them were crushed down or repurposed after the shrine broke down. They're kind of a collector's item now, like old coins or baseball cards. A collector or museum might give you something for it.

Or it could be the Dwarven equivalent of firework poppers. Toss them on the ground and it gives off an interesting and harmless magical effect, like a tiny explosion, a small flash of light, or a ring similar to a bell.

Or it could potentially be a game piece. I'm imagining a game similar to Chinese Checkers or Go, except with square pegs instead of round. There are modern (read: contemporary to the game's time period) versions of this game that have more streamlined rules and are easier to play, but if you could find the matching gameboard, it could be an interesting way to burn an hour.

Or even it could be the keystone to a bridge which once stood in this area centuries ago. When the stone was removed, the bridge collapsed and was eventually buried by erosion (thus explaining the pile of gravel). These stones were special in that they are made to be resistant to the weather and are critical to the structural integrity of their bridges. Whoever took this out really wanted that bridge to not be there.

[Unavenger]

Whatever the player first attempts to use it for turns to be its actual use - if they try to roll it, it's a lucky die; if they try to insert it into their weapon it's a portable enhancement-holder, and so forth.

[denthor]

Look at ion stones player throws it up in the air it circles head gives affect to one person. Even if not D&D. Not eating is great.

[Bohandas]

They're movable type pieces for an experimental system of mass-producing magic scrolls

[Cealocanth]

They're movable type pieces for an experimental system of mass-producing magic scrolls

That's actually a brilliant idea.

[DuctTapeKatar]

They're movable type pieces for an experimental system of mass-producing magic scrolls

I think we have a winner. I can't beat that.

[Mutazoia]

I think we have a winner. I can't beat that.

The great Arch Mage Guttenberg would like to have his movable type face back.

[Jay R]

Its a small charm designed to help prevent a dead body rising to become undead...

And they just picked it up in a graveyard, where it was doing its job.

The party has just released the village wraith.

-----

You could send them into an old crypt, where they find several embedded in the walls or floor -- each one holding back one undead, who are all released at midnight after the party removes all the stones.

[Bastian Weaver]

They kind of reminds me of the components of a Ward Major from Katherine Kurtz's Deryni books. There are eight little cubes that look just like dice (the hero had trouble explaining that they are actually not a strange dice game), four are white, four are black. Each one has a name (basically they're One to Eight). When activated, white ones stick to black ones. Combined, they can be used to form a powerful protection spell.

[Coventry]

Or, maybe you could pull something like what happened to Roger on the-whiteboard ... no group can resist a shiny red button!

The second series starts here, and goes 10 strips.

[Excession]

They're movable type pieces for an experimental system of mass-producing magic scrolls

The creator of these things tried to print a teleport scroll with them, but a mechanical failure activated the spell and scattered the pieces all over.

[username1]

Let them find many more and come upon a door they fit into. Make it a puzzle to match the runes with the clues. However have one stone missing, the party has not acquired. This makes it more real then “we found a bunch of stones in random places”. Sure the places are random, but they aren’t just given to them. Make a quest to find the stone.

[Bohandas]

The creator of these things tried to print a teleport scroll with them, but a mechanical failure activated the spell and scattered the pieces all over.

That's excellent! I couldn't figure out a reason why they'd be scattered everywhere, but that proposal fits perfectly!