He Is the Plumber for Castle Dracula: In Castlevania: Lords of Shadows -- Mirror of Fate, you run across several skeleton knights in the bowels of Dracula's castle. These often have notes attached to them, and one of them reads...
The terrible state of the pipes down here would perturb even my brother Mario.
Some parts have rusted terribly, while others are covered with fungus due to the high humidity.
Not all the mushrooms look good to eat either. Who knows what might happen if I eat one?
Congratulations! You just found Luigi's corpse!
See also: Ten Things You Probably Didn't Know About the Sega Dreamcast
Luigi Gave Bowser His Most Humiliating Defeat: Mario has these epic battles with the King of the Koopas, but Luigi topped all of that with the power of pantsing. In the ending of the DOS version of Mario Is Missing, Luigi confronts Bowser and removes his carapace, leaving him in polka-dotted boxers and too embarrassed to further face Luigi. When Bowser finally comes crawling back to beg for his shell, Luigi tells him he threw it off the balcony, and when Bowser looks, Luigi kicks him out of a window to land in the snow.
Yeah...somehow that seems a lot worse than dumping him in a pit of lava.
He Can Play the Violin: In WarioWare: Smooth Moves, Luigi shows off some considerable violin skills. He shares his name with composer Luigi Boccherini, who gained considerable fame for playing violin repertoire on the cello and wrote a series of string quartets that are popular to this day.
He Can Build a Giant Robot Version of His Head: In Super Paper Mario, Luigi is betrayed by some goombas and ends up hypnotized into becoming the antagonist Mr. L, also known as the Green Thunder. In this capacity, he serves as a foil to Mario, even taking on his real brother inside of a giant "Brobot" that looks like Luigi's head. This might be a metaphor for the good-hearted Luigi being trapped inside an artificial construct.
His Voice Actor Has a Severe Problem With Doubles: There are a lot of names associated with portraying Luigi, including John Leguizamo and Danny Wells, but Tony Rosato was the voice behind the Luigi in the Super Mario Bros. 3 cartoons. Sadly, he is also afflicted with Capgras delusion, a mental disorder in which the patient is convinced that loved ones have been kidnapped and replaced with exact doubles. This delusion eventually led to his wife leaving him out of fear for the safety of their daughter, as well as a two-year stint being held without bail in maximum-security lockup.
It's a sad coincidence. Luigi started out as a carbon copy of Mario, and struggles to maintain his identity to this day, while one of the people who portrays him ironically finds himself beset on all sides by imaginary doubles.
Jef has a new story, a tale of headless strippers and The Rolling Stones, available now in Broken Mirrors, Fractured Minds. You can also connect with him on Facebook.