Mysterious-Dungeon Simulation Game

From Zelda Wiki.org

In The Minish Cap, there is a store in the main square of Hyrule Town with a purple ghost as a sign. This is the place of Simon's Simulation, also known as The Mysterious-Dungeon Simulation Game, which gets its name from the Simon Figurine. In this mini-game, Link falls asleep and is in a room where many different monsters will spawn. This will happen a couple of times. When you defeat all of them, a chest will appear in the middle of the room containing a prize. The cost is 10 Rupees to start. If you die in the Simulation, you will go to the Game Over Screen.