Skeleton Key

The Skeleton Key is a item in Risk of Rain that opens all the chests on the screen.
 * Using this item on a golden chest will unlock the item "Captain's Brooch". Golden chests spawn in the last two levels and are identifiable by their high price and always yield items. One of these chests is found consistently in the Risk of Rain (Level), under the second and third cargo bays.

Trivia

 * When this item is picked up, it is labeled as "Explorer's Key".
 * This item "May be" a reference to SCP-005, Which is named as "The skeleton Key" and it can open any type of lock.
 * This item may also be a reference to the 'Elder Scrolls' series of games, most notably IV - Oblivion and V - Skyrim. This is due to the Skeleton Key not only being a divine artifact that functions in the exact same way as it does in Risk of Rain (unbreakable lockpick, but also opens literally anything, physical or not) in these games, but also due to the fact that in Skyrim, the Thieves Guild does indeed mention that in the wrong hands, the Skeleton Key could render the Thieves Guild 'obsolete' ('obsolete' isn't actually said), and without it, the Thieves Guild is running low on luck.

Gallery
Skeleton Key