When Mario gets enraged after his Hunger Meter only increases by 1% from eating spaghetti for 2 hours, he gives up and gives the game to Luigi.
Thus starting Luigi Simulator. In Luigi Simulator, it is like the original game, but Mario is replaced by Luigi instead. He first wakes up instead of appearing with a "pop", walks while "being awesome" instead of walking and seeing Toad, then being forced to "kill it before it lays eggs," and repeatedly says "Go Weegee!".
While at the Castle Luigi Simulator is taken over by Wario, causing a new sexy mode, called "Wario Simulator", to appear. The mode is then taken back by Mario, thus returning the game to its original state.
Luigi Simulator was destroyed along with all other things and characters in the game/cartridge when Super Saiyan Mario throws the cartridge into the Sun, thus marking the end of Mario Simulator.