Haunted Jar

A distressed looking jar covered in dust, dirt, and grim rests alone on an otherwise empty shelf. For a brief moment, you could swear that you saw a gaunt face drift past.

This is an item that has a lot of potential, but is also completely up to both DM and Player to really tap into it.

One option is to just use it as a great distraction; throw it into a crowd and watch it all happen. Or just grenade your enemies with a hostile specter! Good deal of chaos to be had there...

But if you're looking for more, think about the concept of "Hostile"... That don't mean straight out attack at the first opportunity, it just means they aren't friendly or helpful to your party members, but that's to mean that you can't work with them. The possibilities are endless! This could be the cage for a big campaign level boss that other's are driven to free for themselves. Or some poor fool who thought they found a way to cheat death but it went terribly wrong, but they have valuable information that they will only share once released. Or even still, a chosen hero that was sealed away until their proper time to fulfill whatever prophesy they are meant to quest for.

These are just a few of many possible ways to handle this very simple item. And there are no rules in saying that you as the DM can't change this item either. Want to have a reoccurring helper for your party? Let the jar be reusable and the ghost can pop in and out at will! Just have your party gain the trust of the ghost somehow and be willing to help. Or you can have the captured possess a party member for a lot of crazy fun!

Anyway, the item is now yours to do as you see fit! Have fun!