The Briefcase is a rare ingredient in Adopt Me! which can be obtained from opening Monkey Boxes (
600 or 
195) and through trade.
If a player combines 3 Briefcases (by talking to the Business Monkey in the Monkey Fairground), they can be used to transform a normal Monkey into a Business Monkey.
This rare item is no longer obtainable and can now only be gained through trading.
It is put in the Toys section of a player's inventory.
Trivia
- The Briefcase is only obtainable when the Monkey Fairground Event is around. During the time it is unobtainable, it also cannot be traded in for the Business Monkey.
- When a player interacts with the Briefcase when the Monkey Fairground is not around, a message pops up reading “I wonder what this does...”
- Some players may get this confused as a pet wear item.