The Cursed Treasure

[Dr paradox]

So, I'm writing a module in which there's a separate treasure worth as much as the rest of the tomb combined, but it's cursed with a certain amount of telegraphing.

The question is, what form should the curse take, and how should it be broken?

For the curse, I was picturing a specter that appears to be a real person - a cloaked figure that they see at a distance at first. Perhaps they arrive at a tavern and find that such a person has been asking after them. Eventually, though, they wake in the middle of the night to find this figure attacking them out of nowhere. Once they kill them, the figure evaporates into smoke, then reappears at a distance once again. As time goes on, it starts picking more and more inopportune times to strike, and attacks with greater frequency - makes in impossible to prepare spells, then makes in impossible to take a long rest.

Alternately, should it be more Tutankhamen, and take the form of a slow but insidious illness that no medicine can cure? Just straight mummy rot?

For reference, this is first level D&D. Mechanics aren't really necessary, I'm just looking for theming appropriate to a low-er magic, sword and sorcery tone.

[Koo Rehtorb]

An aura around them that makes people distrust and fear them. Probably starting small with people shooting them wary glances, ending with mobs driving them out of towns with fire and pitchforks.

[AnBe]

I have 3 ideas
1. Each time they try to make a stealth check, there is a 1/20 chance a magical horn will appear and blow really loud, announcing their presence to all. As the curse endures longer, the chance gets higher.
2. The curse slowly transforms them into weird, aberration-like mutants.
3. A chance of spell failure. This can go for arcane casters as well as divine ones.

[Mastikator]

Start off with vague figures in the shadows, turns out it's nothing.
Then it's sounds that wake them up in the middle of the night, the sound came from the cursed treasure.
Then it's a person that runs off into the night on appearance, it looked as though they're trying to steal the cursed treasure.
Then it's words said by people who didn't say it, people who want to steal the cursed treasure.
People who aren't really there shadowing the PC.
Finally you spot someone steal the cursed treasure, it's gone, the person denies everything. They claim you misplaced it but you saw them take it.

You turn on your friends to protect the treasure. The way to break the curse is to put it back, the benefits of the treasure should make this a terrible option.

[FreddyNoNose]

How about the attacks happen when the character tries to travel away from the location. But isn't attacked when moving in a specific direction. AKA, you are allowed to go North West. After some time traveling North West, suddenly the character is blocked from going North West or any other direction. So they can search the local area, say wilderness and about a quarter to half mile around. Some where is way to go underground where the solution to the curse can be encountered.