Ominous and cursed trinkets? [closed]

On my group’s first session, at the end of the boss, they found a trinket. It is tooth-shaped. And I have no idea of what it should do, but I thought it would be interesting to give them something to think about. However, I’m not really sure of what to do with it. I can keep delaying it and give very vague clues as they probe cities to what it may be.

The group will now proceed to the Phandelin for the 1st session of the Dragon of Icespire Peak. Could it have any magical properties? Could it be crucial to defeat the white dragon? Or perhaps later on in the story?

My question is if you have suggestions for ominous trinkets or effects that it could have? Something that could have both a cursed and good effect on the party perhaps? Are there such items to your knowledge?

Thanks in advance