User blog comment:Prosciutto With Horns/Forever lost Super Mario 64 creepypasta/@comment-30354437-20191001065505

I searched "Super Mario 64" on Creepypasta Wikia and found a pasta in which Mario finds Luigi hanged in a "cottage" (actual word from the creepypasta) and it is mentioned earlier that the level is oddly called "TURN BACK" instead of "Big Bomb-Omb on the Summit". It is also in the Historical Archive category so it must be the one you are talking about.