Crystal Ball

First seen in Super Mario Brothers 2. Birdo spits it out after being defeated. Lifting it opens the door to the next level.

It was later seen in the Paper Mario series as the main magic tool for Merlon's family.

It was seen again in Luigi's Mansion, used by Madame Clairvoya to see the furture and other things.

It was seen once more in Mario Party 6, in the Seer Terror mini-game.