📍 Where to find it
Crates (Frozen Sewer) — both the Common and the Rare event
🛠 What it's for
Feed the starving ratman in the common event (rations, the Harpy Egg, the Grain Sack or the Big Fish all work); the rare event gives the key on any option. Use it at the Void's Statue (North) node to cross the bridge to the Ruins without a skill check.