The phrase you are referring to is likely a phonetic or mistranslated version of Meikyuu Black Company (The Dungeon of Black Company)
thedungeoninyarnyonekinjidanchinoko better thedungeoninyarnyonekinjidanchinoko better
The "dungeon appearing in the modern world" trope is everywhere. From Solo Leveling to boundless amounts of Isekai-adjacent light novels, we’ve seen it all. However, The Dungeon in My Yard: Nanoka no Ore wa Kinjidanchi no Ko is generating serious buzz for doing things differently. The phrase you are referring to is likely
Characters who are motivated by greed or comfort rather than altruism. we’ve seen it all. However
Special events that trigger based on how "well" or "efficiently" the player is managing their "Black Company" of explorers.