Super Mario Bros. 35--a multiplayer battle royale take on the original Super Mario Bros.--is one of the strangest games Nintendo has released in a long time, and it's garnered quite a bit of attention recently. Now, some clever players have discovered that you can play as Luigi in the game, just like in the original Super Mario Bros., though they haven't quite agreed on how to unlock him.
The original Reddit post claimed that you had to reach Star Rank, which is progress level 100 in the game, before you could play as Luigi. Follow-up posts and replies from fans seem to indicate that you have to complete every stage in the game at least once, including the final Bowser in 8-4. It's unclear if Star Rank is also required. Players simply hold L during the matchmaking process, and they'll play as Luigi instead of Mario.