|First appearance||Mario is Missing! (1993)|
The important stone is an item solely in the NES release of Mario is Missing!. It is a single rock that laid on the highest point of Montreal's Mount Royal. When Koopa Troopas invade the city, they steal this rock, and the entire mountain is closed to the public until it is returned. Luigi eventually enters the city and takes it back, then asks the locals about it as he does not know where it belongs. All of them recognize the rock as belonging to the mountain. After gathering enough information, Luigi takes it to Mount Royal's information booth and answers a question to prove the item's legitimacy, whereupon the mountain is reopened.
- Boy: "The mountain may not be royal, but it’s big. You’ll climb 764 feet to put that stone back."
- Tourist: "Get a giant backpack, that stone belongs on Mount Royal."
- Business Woman: "I hope you have a good altitude. You’ll have to mount Mount Royal to plant that stone where it belongs."
- Scientist: "I hope you have a good altitude. You’ll have to mount Mount Royal to plant that stone where it belongs."
- Police Officer: "Put the stone on Mount Royal. And please replace one of the 158 bulbs that burned out."