In game description:
"Place this in your world to be used in your Gateways To Adventure! Players can pick it up by punching it. They lose it if they leave your world. If you start a line or button with "+K", that line or button will only appear if the player has this item. "-K" will only appear if they don't have it. Use "#K" instead of "+K" on a button, and it will use up this item when they use the button, returning it to where they found it."
Rarity: 64
To grow, plant a Adventure Item - Key' Seed. (Or splice a Wall Like An Egyptian Seed with a Jail Door Seed)
Adventure Item - Key
Adventure Pack
This item can also be obtained from the Adventure Pack for 8,000 gems.
This item is used in Crafting Adventures.