Lurker Skin Pouch is a special item that can provide portable storage for the player.
The Lurker Skin Pouch can optionally used as part of the Radial Equipment Menu, which is opened by pressing F (by default). It displays any pouch equipped onto the player (in red tab) as well as pouches in their inventory (in green tab); a pouch can be both equipped and 'unquipped' with a left click. This allows for easy management of pouch equipping; however, note that only one pouch can be equipped at a time. While equipped, the pouch will render on the player's back.
Lurker Skin Pouches can be opened with a right-click on the unequipped item or with a hotkey (C by default, prioritizes any equipped pouch first), displaying additional inventory slots with which one can store items inside like a chest and open again when needed; only, it is stored in an item you can carry around rather than a block. When first crafted, Lurker Skin Pouches have only 9 item slots. However, they can be upgraded up to five times, each time adding an additional 9 slots to the pouch's storage, up to a maximum possible 54 item slots (the same as a double chest). Note that 'nested storage' is not possible; that is, you cannot put one pouch inside another to exploit infinite storage.
When sneak-right clicked, the pouch will open a GUI where a custom name for the pouch can be input and saved. This makes it easy for one to organize their pouches based on what items they mean to put inside.