If you're looking for the item, see The Smoking Mirror (item).
The Smoking Mirror can be reached with the The Smoking Mirror Buff. It cannot simply be a random event.
In the event, all items in all players' inventories (excluding Soulbound items) are shown to you, including your own. (There are max. 200 items shown; if there are more than 200 items which could be shown, 200 are randomly selected.) You can choose 1 of the items shown to you and steal it, though you could choose to steal nothing. Note the following:
- This event is prioritized over most other events.
- The shown items have the order randomized compared with players' inventories.
- You aren't told who the owner of a shown item is, and there can be multiple copies of an item with identical appearance such that there's no way to differentiate even between your own item and another player's. (If you do choose your own item, you can't choose another.)
- You are able to see any enchantments that an item has at the moment the event begins by mousing over the item (or, for Fireproof and Ethereal, seeing the changed icon).
- You are able to see which specific spell a shown magical item is charged with by mousing over the item.
- If a shown item is made Soulbound or is somehow removed from the game before an item is chosen, the item will still appear as an option, though it will not be stolen if chosen. (You can't choose another item in this case.)